Granite yog ib hom pob zeb igneous uas raug rho tawm vim nws lub zog heev, qhov ceev, kev ruaj khov, thiab kev tiv taus corrosion. Tab sis granite kuj muaj ntau yam siv tau - nws tsis yog rau cov square thiab rectangles xwb! Qhov tseeb, Peb ua haujlwm nrog cov khoom granite uas tau tsim los ntawm cov duab, cov ces kaum, thiab cov nkhaus ntawm txhua qhov sib txawv tsis tu ncua - nrog cov txiaj ntsig zoo heev.
Through our state of the art processing, cut surfaces can be exceptionally flat. These qualities make granite the ideal material to create custom-size and custom-design machine bases and metrology components. Granite is:
■ siv tau tshuab
■ tiaj tiaj thaum txiav thiab ua tiav
■ tiv taus xeb
■ ruaj khov
■ kav ntev
Cov khoom granite kuj yooj yim ntxuav. Thaum tsim cov qauv tsim tshwj xeeb, nco ntsoov xaiv granite rau nws cov txiaj ntsig zoo tshaj plaws.

COV QAUV / COV DAIM NTAWV THOV KEV HNAV SIAB
Cov granite uas ZHHIMG siv rau peb cov khoom siv phaj nto txheem muaj cov ntsiab lus quartz siab, uas muab kev tiv thaiv zoo dua rau kev hnav thiab kev puas tsuaj. Peb cov xim Superior Black muaj cov dej nqus tsawg, txo qhov ua tau ntawm koj cov ntsuas precision xeb thaum teeb tsa ntawm cov phaj. Cov xim ntawm granite uas ZHHIMG muab ua rau muaj kev ci ntsa iab tsawg dua, uas txhais tau tias qhov muag tsawg dua rau cov tib neeg siv cov phaj. Peb tau xaiv peb cov hom granite thaum xav txog kev nthuav dav thermal hauv kev siv zog kom qhov no tsawg kawg nkaus.

CUSTOM APPLICATIONS
Thaum koj daim ntawv thov xav tau lub phaj nrog cov duab tshwj xeeb, cov ntxig xov, qhov lossis lwm yam kev siv tshuab, koj yuav xav xaiv cov khoom siv zoo li Black Jinan Black. Cov khoom siv ntuj no muaj kev ruaj khov zoo, kev co zoo heev, thiab kev siv tshuab tau zoo dua.

Nws yog ib qho tseem ceeb uas yuav tsum nco ntsoov tias xim ib leeg tsis yog qhov qhia txog qhov zoo ntawm lub pob zeb. Feem ntau, xim granite muaj feem cuam tshuam ncaj qha rau qhov muaj lossis tsis muaj cov zaub mov, uas tej zaum yuav tsis muaj feem cuam tshuam rau qhov zoo uas ua rau cov khoom siv phaj nto zoo. Muaj cov granites liab dawb, grey, thiab dub uas zoo heev rau cov phaj nto, nrog rau cov granites dub, grey, thiab liab dawb uas tsis haum rau kev siv precision. Cov yam ntxwv tseem ceeb ntawm granite, raws li lawv hais txog nws siv ua cov khoom siv phaj nto, tsis muaj dab tsi ua rau xim, thiab yog raws li nram no:
■ Kev Ruaj Khoov (kev khoov thaum muaj kev thauj khoom - qhia los ntawm Modulus of Elasticity)
■ Qhov Nyuaj
■ Qhov Ceev
■ Kev tiv thaiv kev hnav
■ Kev Ruaj Ntseg
■ Qhov muaj qhov porosity

Peb tau sim ntau yam khoom siv granite thiab piv rau cov khoom no. Thaum kawg peb tau txais qhov tshwm sim, Jinan dub granite yog cov khoom zoo tshaj plaws uas peb tau paub. Indian Black granite thiab South African granite zoo ib yam li Jinan Black Granite, tab sis lawv cov khoom siv lub cev tsawg dua Jinan Black Granite. ZHHIMG yuav nrhiav ntau cov khoom siv granite hauv ntiaj teb thiab piv rau lawv cov khoom siv lub cev.

Yog xav tham ntxiv txog cov granite uas yog rau koj qhov project, thov hu rau pebinfo@zhhimg.com.

Cov chaw tsim khoom sib txawv siv cov qauv sib txawv. Muaj ntau tus qauv hauv ntiaj teb.
DIN Txheem, ASME B89.3.7-2013 lossis Federal Specification GGG-P-463c (Granite Surface Plates) thiab lwm yam ua lub hauv paus rau lawv cov lus qhia.

Thiab peb tuaj yeem tsim cov granite precision inspection plate raws li koj xav tau. Txais tos tiv tauj peb yog tias koj xav paub ntau ntxiv txog ntau cov qauv.

Qhov tiaj tiaj yog suav tias yog txhua qhov chaw ntawm qhov chaw uas muaj nyob hauv ob lub dav hlau sib luag, lub dav hlau hauv paus thiab lub dav hlau ru tsev. Kev ntsuas qhov deb ntawm cov dav hlau yog qhov tiaj tiaj tag nrho ntawm qhov chaw. Qhov kev ntsuas qhov tiaj tiaj no feem ntau muaj kev kam rau siab thiab tej zaum yuav suav nrog kev xaiv qib.

Piv txwv li, qhov kev kam rau siab rau peb qib txheem tau txhais nyob rau hauv tsoomfwv qib siab raws li txiav txim siab los ntawm cov qauv hauv qab no:
■ Qib Kuaj Mob AA = (40 + kab pheeb ces kaum/25) x .000001" (ib sab)
■ Qib Tshuaj Xyuas A = Qib Chaw Kuaj Mob AA x 2
■ Chav Cuab Yeej Qib B = Chav Kuaj Mob Qib AA x 4.

Rau cov phaj nto loj, peb lav qhov kev kam rau siab uas tshaj qhov yuav tsum tau ua ntawm cov lus qhia no. Ntxiv rau qhov tiaj tiaj, ASME B89.3.7-2013 & Federal Specification GGG-P-463c hais txog cov ncauj lus suav nrog: kev ntsuas rov ua dua qhov tseeb, cov khoom siv ntawm cov phaj granites nto, qhov tiav ntawm qhov chaw, qhov chaw txhawb nqa, qhov tawv, cov txheej txheem lees txais ntawm kev tshuaj xyuas, kev teeb tsa cov ntawv ntxig xov, thiab lwm yam.

ZHHIMG cov phaj granite thiab cov phaj tshuaj xyuas granite ua tau raws li lossis tshaj tag nrho cov kev cai teev tseg hauv cov lus qhia no. Tam sim no, tsis muaj cov lus qhia meej rau cov phaj granite kaum sab xis, cov sib luag, lossis cov plaub fab tswv.

Thiab koj tuaj yeem nrhiav cov qauv rau lwm cov qauv hauvDOWNLOAD.

Ua ntej, nws yog ib qho tseem ceeb kom khaws lub phaj kom huv. Cov hmoov av uas ya los ntawm huab cua feem ntau yog qhov ua rau hnav thiab tsim kua muag ntau tshaj plaws ntawm lub phaj, vim nws feem ntau nkag mus rau hauv cov khoom ua haujlwm thiab cov chaw sib cuag ntawm cov ntsuas. Qhov thib ob, npog koj lub phaj kom tiv thaiv nws ntawm hmoov av thiab kev puas tsuaj. Lub neej hnav tuaj yeem ntev dua los ntawm kev npog lub phaj thaum tsis siv, los ntawm kev tig lub phaj tsis tu ncua kom ib cheeb tsam tsis tau txais kev siv ntau dhau, thiab los ntawm kev hloov cov hlau sib cuag ntawm qhov ntsuas nrog cov carbide pads. Tsis tas li ntawd, tsis txhob muab zaub mov lossis dej qab zib tso rau ntawm lub phaj. Nco ntsoov tias ntau yam dej qab zib muaj cov pa roj carbonic lossis phosphoric acid, uas tuaj yeem yaj cov zaub mov mos dua thiab tawm hauv cov qhov me me hauv qhov chaw.

Qhov no nyob ntawm seb lub phaj siv li cas. Yog tias ua tau, peb xav kom koj ntxuav lub phaj thaum pib hnub (lossis ua haujlwm) thiab dua thaum kawg. Yog tias lub phaj qias neeg, tshwj xeeb tshaj yog cov roj lossis cov kua nplaum, nws yuav tsum tau ntxuav tam sim ntawd.

Ntxuav lub phaj tsis tu ncua nrog cov kua lossis ZHHIMG cov tshuaj ntxuav phaj nto tsis muaj dej. Kev xaiv cov tshuaj ntxuav yog qhov tseem ceeb. Yog tias siv cov tshuaj yaj uas yaj tau yooj yim (acetone, lacquer thinner, cawv, thiab lwm yam) qhov kev ua pa yuav ua rau qhov chaw txias, thiab ua rau nws puas. Hauv qhov no, nws yog ib qho tsim nyog yuav tsum cia lub phaj rov qab zoo li qub ua ntej siv nws lossis qhov yuam kev ntsuas yuav tshwm sim.

Lub sijhawm uas yuav tsum tau ua kom lub phaj rov qab zoo li qub yuav txawv raws li qhov loj ntawm lub phaj, thiab qhov ntau ntawm kev txias. Ib teev yuav tsum txaus rau cov phaj me dua. Tej zaum yuav xav tau ob teev rau cov phaj loj dua. Yog tias siv cov tshuaj ntxuav dej, kuj yuav muaj qee qhov kev ua kom txias.

Lub phaj kuj tseem yuav khaws cov dej, thiab qhov no yuav ua rau cov hlau uas kov qhov chaw xeb. Qee cov tshuaj ntxuav kuj tseem yuav tso cov khoom seem nplaum tom qab lawv qhuav, uas yuav nyiam cov hmoov av hauv huab cua, thiab ua rau kev hnav ntau dua, es tsis yog txo nws.

Qhov no nyob ntawm seb lub phaj siv thiab ib puag ncig li cas. Peb xav kom lub phaj tshiab lossis cov khoom siv granite precision tau txais kev kho dua tshiab tag nrho hauv ib xyoos ntawm kev yuav khoom. Yog tias lub phaj granite nto yuav pom kev siv ntau, nws yuav zoo dua kom luv lub sijhawm no mus rau rau lub hlis. Kev tshuaj xyuas txhua hli rau qhov yuam kev ntsuas rov ua dua siv lub tshuab hluav taws xob, lossis cov cuab yeej zoo sib xws yuav qhia txog cov chaw hnav thiab tsuas yog siv ob peb feeb xwb los ua. Tom qab cov txiaj ntsig ntawm kev kho dua tshiab thawj zaug tau txiav txim siab, lub sijhawm kho dua tshiab yuav raug ncua lossis luv dua raws li tso cai lossis xav tau los ntawm koj lub kaw lus zoo sab hauv.

Peb tuaj yeem muab kev pabcuam los pab koj tshuaj xyuas thiab kho koj lub phaj granite nto.

Muaj ntau yam ua rau muaj kev hloov pauv ntawm kev ntsuas:

• Qhov chaw tau ntxuav nrog cov tshuaj kub lossis txias ua ntej calibration, thiab tsis tau tso cai rau lub sijhawm txaus los ua kom zoo li qub.
• Lub phaj tsis txhawb nqa zoo
• Kev hloov pauv kub
• Cov Qauv
• Tshav ntuj ncaj qha los yog lwm yam cua sov rau ntawm qhov chaw ntawm lub phaj. Xyuas kom tseeb tias lub teeb saum toj tsis ua rau qhov chaw sov.
• Kev hloov pauv ntawm qhov kub thiab txias ntawm lub caij ntuj no thiab lub caij ntuj sov (Yog tias ua tau, paub qhov kub thiab txias ntawm lub sijhawm ntsuas.)
• Phaj tsis tau tso cai rau lub sijhawm txaus los ua kom rov zoo li qub tom qab xa khoom
• Siv cov khoom siv tshuaj xyuas tsis raug lossis siv cov khoom siv tsis tau calibrated
• Kev hloov pauv ntawm qhov chaw los ntawm kev hnav

Muaj pes tsawg hom qhov ntawm precision granite?

Cov Qhov rau ntawm Precision Granite Components

Rau ntau lub Hoobkas, chav tshuaj xyuas thiab chaw soj ntsuam, cov phaj granite nto precision yog siv los ua lub hauv paus rau kev ntsuas qhov tseeb. Vim tias txhua qhov kev ntsuas linear nyob ntawm qhov chaw siv qhov tseeb uas qhov ntev kawg tau coj los, cov phaj nto muab qhov chaw siv qhov zoo tshaj plaws rau kev tshuaj xyuas ua haujlwm thiab kev teeb tsa ua ntej ua haujlwm. Lawv kuj yog lub hauv paus zoo tagnrho rau kev ntsuas qhov siab thiab qhov chaw ntsuas. Ntxiv mus, qib siab ntawm qhov tiaj tus, kev ruaj khov, qhov zoo tag nrho thiab kev ua haujlwm ua rau lawv yog qhov kev xaiv zoo rau kev teeb tsa cov tshuab kho tshuab, hluav taws xob thiab kho qhov muag. Rau ib qho ntawm cov txheej txheem ntsuas no, nws yog qhov tseem ceeb kom khaws cov phaj nto calibrated.

Repeat Measurements and Flatness

Ob qho tib si qhov tiaj tiaj thiab kev ntsuas rov ua dua yog qhov tseem ceeb kom ntseeg tau tias qhov chaw raug. Qhov tiaj tiaj tuaj yeem suav hais tias yog txhua qhov chaw ntawm qhov chaw uas muaj nyob hauv ob lub dav hlau sib luag, lub dav hlau hauv paus thiab lub dav hlau ru tsev. Kev ntsuas qhov deb ntawm cov dav hlau yog qhov tiaj tiaj tag nrho ntawm qhov chaw. Qhov kev ntsuas qhov tiaj tiaj no feem ntau muaj kev kam rau siab thiab tej zaum yuav suav nrog kev xaiv qib.

The flatness tolerances for three standard grades are defined in the federal specification as determined by the following formula:

DIN Txheem, GB Txheem, ASME Txheem, JJS txheem ... txawv teb chaws nrog txawv sawv ...

Xav paub ntxiv txog tus qauv.

In addition to flatness, repeatability must be ensured. A repeat measurement is a measurement of local flatness areas. It is a measurement taken anywhere on the surface of a plate that will repeat within the stated tolerance. Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.

Yuav kom ntseeg tau tias lub phaj nto ua tau raws li qhov tiaj tiaj thiab rov ntsuas cov lus qhia, cov chaw tsim khoom ntawm cov phaj granite nto yuav tsum siv Federal Specification GGG-P-463c ua lub hauv paus rau lawv cov lus qhia. Cov qauv no hais txog qhov tseeb ntawm kev ntsuas rov ua dua, cov khoom siv ntawm cov phaj granite nto, qhov tiav ntawm qhov chaw, qhov chaw txhawb nqa, qhov nruj, cov txheej txheem lees txais ntawm kev tshuaj xyuas thiab kev teeb tsa cov ntxig xov.

Checking Plate Accuracy

Los ntawm kev ua raws li ob peb txoj cai yooj yim, kev nqis peev rau hauv lub phaj granite nto yuav tsum kav ntev ntau xyoo. Nyob ntawm seb siv lub phaj li cas, ib puag ncig hauv khw thiab qhov tseeb uas xav tau, qhov zaus ntawm kev kuaj xyuas qhov tseeb ntawm lub phaj nto txawv. Ib txoj cai dav dav yog rau lub phaj tshiab kom tau txais kev kho dua tshiab tag nrho hauv ib xyoos ntawm kev yuav khoom. Yog tias lub phaj siv ntau zaus, nws raug nquahu kom luv lub sijhawm no mus rau rau lub hlis.

Before a surface plate has worn beyond specification for overall flatness, it will show worn or wavy posts. Monthly inspection for repeat measurement errors using a repeat reading gage will identify wear spots. A repeat reading gage is a high-precision instrument that detects local error and can be displayed on a high magnification electronic amplifier.

An effective inspection program should include regular checks with an autocollimator, providing actual calibration of overall flatness traceable to National Institute of Standards and Technology (NIST). Comprehensive calibration by the manufacturer or an independent company is necessary from time to time.

Variations Between Calibrations

Qee zaum, muaj qhov sib txawv ntawm kev ntsuas qhov chaw ntawm lub phaj nto. Qee zaum tej yam xws li kev hloov pauv ntawm qhov chaw los ntawm kev hnav, kev siv cov khoom siv tshuaj xyuas tsis raug lossis kev siv cov khoom siv tsis tau ntsuas tuaj yeem ua rau muaj qhov sib txawv no. Txawm li cas los xij, ob qho tseem ceeb tshaj plaws yog qhov kub thiab kev txhawb nqa.

One of the most important variables is temperature. For instance, the surface might have been washed with a hot or cold solution prior to calibration and not allowed sufficient time to normalize. Other causes of temperature change include drafts of cold or hot air, direct sunlight, overhead lighting or other sources of radiant heat on the surface of the plate.

There also can be variations in the vertical temperature gradient between winter and summer. In some cases, the plate is not allowed sufficient time to normalize after shipment. It is a good idea to record the vertical gradient temperature at the time the calibration is performed.

Another common cause for calibration variation is a plate that is improperly supported. A surface plate should be supported at three points, ideally located 20% of the length in from the ends of the plate. Two supports should be located 20% of the width in from the long sides, and the remaining support should be centered.

Only three points can rest solidly on anything but a precision surface. Attempting to support the plate at more than three points will cause the plate to receive its support from various combinations of three points, which will not be the same three points on which it was supported during production. This will introduce errors as the plate deflects to conform to the new support arrangement. Consider using steel stands with support beams designed to line up with the proper support points. Stands for this purpose are generally available from the surface plate manufacturer.

If the plate is properly supported, precise leveling is only necessary if an application specifies it. Leveling is not necessary to maintain the accuracy of a properly supported plate.

Extend Plate Life

Ua raws li ob peb cov lus qhia yuav txo qhov hnav ntawm lub phaj granite thiab thaum kawg, ntev nws lub neej.

Ua ntej, nws yog ib qho tseem ceeb kom lub phaj huv si. Cov hmoov av uas ya saum huab cua feem ntau yog qhov ua rau lub phaj puas tsuaj loj tshaj plaws, vim nws feem ntau nkag mus rau hauv cov khoom ua haujlwm thiab cov chaw sib cuag ntawm cov ntsuas.

It also is important to cover plates to protect it from dust and damage. Wear life can be extended by covering the plate when not in use.

Tig lub phaj tsis tu ncua kom ib cheeb tsam tsis tau siv ntau dhau. Tsis tas li ntawd, nws raug pom zoo kom hloov cov hlau sib txuas ntawm qhov ntsuas nrog cov carbide pads.

Avoid setting food or soft drinks on the plate. Many soft drinks contain either carbonic or phosphoric acid, which can dissolve the softer minerals and leave small pits in the surface.

Where to Relap

Thaum lub phaj granite xav tau kev kho dua tshiab, xav txog seb puas yuav tsum tau ua qhov kev pabcuam no ntawm qhov chaw lossis ntawm qhov chaw calibration. Nws yeej ib txwm zoo dua kom lub phaj rov qab kho dua ntawm lub Hoobkas lossis chaw tshwj xeeb. Txawm li cas los xij, yog tias lub phaj tsis hnav dhau, feem ntau nyob hauv 0.001 nti ntawm qhov kev kam rau siab xav tau, nws tuaj yeem rov ua dua tshiab ntawm qhov chaw. Yog tias lub phaj hnav mus rau qhov chaw uas nws ntau dua 0.001 nti tawm ntawm qhov kev kam rau siab, lossis yog tias nws tsis zoo lossis raug khawb, ces nws yuav tsum raug xa mus rau lub Hoobkas rau kev sib tsoo ua ntej rov ua dua.

A calibration facility has the equipment and factory setting providing the optimum conditions for proper plate calibration and rework if necessary.

Yuav tsum tau ua tib zoo xaiv tus kws kho kom raug thiab kho dua tshiab hauv qhov chaw. Thov kom tau daim ntawv pov thawj thiab xyuas kom meej tias cov khoom siv uas tus kws kho yuav siv puas muaj kev kho kom raug. Kev paub dhau los kuj yog ib qho tseem ceeb, vim tias nws siv sijhawm ntau xyoo los kawm paub yuav ua li cas kom raug.

Critical measurements start with a precision granite surface plate as a baseline. By ensuring a reliable reference by using a properly calibrated surface plate, manufacturers have one of the essential tools for reliable measurements and better quality parts.Q

Checklist for Calibration Variations

1. Ua ntej calibration, qhov chaw ntawd tau ntxuav nrog cov tshuaj kub lossis txias thiab tsis tau muab sijhawm txaus los ua kom zoo li qub.

2. Lub phaj tsis txhawb nqa zoo.

3. Kev hloov pauv kub.

4. Cov qauv ntawv.

5. Tshav ntuj ncaj qha los yog lwm yam cua sov rau ntawm qhov chaw ntawm lub phaj. Xyuas kom tseeb tias lub teeb saum toj tsis ua rau qhov chaw sov.

6. Kev hloov pauv ntawm qhov kub thiab txias ntawm lub caij ntuj no thiab lub caij ntuj sov. Yog tias ua tau, paub qhov kub thiab txias ntawm lub sijhawm ntsuas.

7. Phaj tsis tau tso cai rau lub sijhawm txaus los ua kom rov zoo li qub tom qab xa khoom.

8. Siv cov khoom siv tshuaj xyuas tsis raug lossis siv cov khoom siv uas tsis tau ntsuas.

9. Kev hloov pauv ntawm qhov chaw los ntawm kev hnav.

Tech Tips

• Vim tias txhua qhov kev ntsuas linear nyob ntawm qhov chaw siv qhov tseeb uas qhov kawg tau coj los, cov phaj saum npoo muab qhov chaw siv qhov zoo tshaj plaws rau kev tshuaj xyuas ua haujlwm thiab kev teeb tsa ua ntej ua haujlwm.
• Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.
• Ib qho kev tshuaj xyuas zoo yuav tsum suav nrog kev tshuaj xyuas tsis tu ncua nrog lub autocollimator, muab qhov tseeb calibration ntawm tag nrho flatness traceable rau National Inspection Authority.

Ntawm cov khoom me me uas ua rau granite, ntau tshaj 90% yog feldspar thiab quartz, uas feldspar yog qhov ntau tshaj plaws. Lub feldspar feem ntau yog dawb, grey, thiab nqaij-liab, thiab lub quartz feem ntau yog tsis muaj xim lossis greyish dawb, uas yog cov xim yooj yim ntawm granite. Feldspar thiab quartz yog cov minerals tawv, thiab nws nyuaj rau txav nrog riam hlau. Raws li rau cov chaw tsaus nti hauv granite, feem ntau yog dub mica, muaj qee cov minerals lwm yam. Txawm hais tias biotite yog mos mos, nws lub peev xwm los tiv taus kev ntxhov siab tsis yog qhov tsis muaj zog, thiab tib lub sijhawm lawv muaj me me hauv granite, feem ntau tsawg dua 10%. Qhov no yog cov khoom siv uas granite muaj zog tshwj xeeb.

Lwm qhov laj thawj uas ua rau granite muaj zog yog vim nws cov khoom siv hauv av tau khi ua ke thiab sib koom ua ke. Cov qhov hws feem ntau suav txog tsawg dua 1% ntawm tag nrho cov pob zeb. Qhov no ua rau granite muaj peev xwm tiv taus qhov siab thiab tsis yooj yim nkag mus los ntawm cov dej noo.

Cov khoom siv granite yog ua los ntawm pob zeb uas tsis muaj xeb, tiv taus kua qaub thiab alkali, tiv taus kev hnav zoo thiab lub neej ntev, tsis muaj kev saib xyuas tshwj xeeb. Cov khoom siv granite precision feem ntau yog siv rau hauv kev siv tshuab. Yog li ntawd, lawv hu ua granite precision components lossis granite components. Cov yam ntxwv ntawm granite precision components yog tib yam li cov granite platforms. Kev taw qhia rau cov cuab yeej thiab kev ntsuas ntawm granite precision components: Precision machining thiab micro machining technology yog cov lus qhia tseem ceeb ntawm kev tsim khoom siv tshuab, thiab lawv tau dhau los ua qhov qhia tseem ceeb los ntsuas qib high-tech. Kev txhim kho ntawm kev siv tshuab txiav thiab kev tiv thaiv kev lag luam tsis sib cais los ntawm precision machining thiab micro-machining technology. Granite components tuaj yeem swb tau yooj yim hauv kev ntsuas, tsis muaj kev poob qis. Kev ntsuas qhov chaw ua haujlwm, kev khawb dav dav tsis cuam tshuam rau kev ntsuas qhov tseeb. Granite components yuav tsum tau tsim thiab tsim raws li qhov xav tau ntawm sab kev thov.

Daim ntawv thov teb:

Raws li peb txhua tus paub ntau thiab ntau lub tshuab thiab cov khoom siv xaiv cov khoom siv granite precision.

Cov khoom siv granite yog siv rau kev txav mus los dynamic, linear motors, cmm, cnc, laser tshuab ...

txais tos hu rau peb kom paub ntxiv.

Cov khoom siv ntsuas granite thiab cov khoom siv kho tshuab granite yog ua los ntawm cov pob zeb Jinan Black zoo. Vim lawv qhov kev ua haujlwm siab, lub sijhawm ntev, kev ruaj khov zoo thiab kev tiv thaiv corrosion, lawv tau siv ntau dua thiab ntau dua hauv kev tshuaj xyuas cov khoom lag luam niaj hnub no thiab cov chaw tshawb fawb xws li tshuab aerospace thiab kev tshawb fawb.

Cov txiaj ntsig

---- Ob zaug nyuaj li hlau cam khwb cia;

---- Kev hloov pauv tsawg kawg nkaus ntawm qhov loj me yog vim muaj kev hloov pauv ntawm qhov kub thiab txias;

---- Dawb los ntawm kev ntswj, yog li ntawd tsis muaj kev cuam tshuam ntawm kev ua haujlwm;

---- Tsis muaj burrs lossis protrusions vim yog cov qauv zoo thiab tsis tseem ceeb stickness, uas ua kom muaj qib siab ntawm flatness dhau lub neej ntev kev pabcuam thiab tsis ua rau puas tsuaj rau lwm qhov lossis cov cuab yeej;

---- Kev ua haujlwm tsis muaj teeb meem rau kev siv nrog cov ntaub ntawv sib nqus;

---- Lub neej ntev thiab tsis muaj xeb, ua rau cov nqi kho qis.

Cov phaj granite nto precision yog precision lapped rau tus qauv siab ntawm flatness kom ua tiav qhov tseeb thiab siv ua lub hauv paus rau mounting sophisticated mechanical, electronic thiab optical gauging systems.

Qee qhov tshwj xeeb ntawm cov granite nto phaj:

Kev sib npaug hauv Hardness;

Muaj tseeb raws li cov xwm txheej thauj khoom;

Kev co nqus dej;

Yooj yim rau ntxuav;

Qhwv Tiv Thaiv;

Porosity tsawg;

Tsis yog Abrasive;

Tsis yog-Sib nqus

Cov txiaj ntsig ntawm Granite Surface Plate

First, the rock after a long period of natural aging, uniform structure, coefficient minimum, the internal stress completely disappear, not deformed, so the precision is high.

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Precision Granite Base Can Improve Machine Tool Performances

Requirements are constantly increasing in mechanical engineering in general and in machine tool construction in particular. Achieving maximum precision and performance values without increasing costs are constant challenges to being competitive. The machine tool bed is a decisive factor here. Therefore, more and more machine tool manufacturers are relying on granite. Due to its physical parameters, it offers clear advantages that cannot be achieved with steel or polymer concrete.

Granite is a so-called volcanic deep rock and has a very dense and homogeneous structure with an extremely low coefficient of expansion, low thermal conductivity and high vibration damping.

Below you will discover why the common opinion that granite is mainly only suitable as machine base for high-end coordinate measuring machines is long outdated and why this natural material as a machine tool base is a very advantageous alternative to steel or cast iron even for high-precision machine tools.

We can manufacture granite components for dynamic motion, granite components for linear motors, granite components for ndt, granite components for xray, granite components for cmm, granite components for cnc, granite precision for laser, granite components for aerospace, granite components for precision stages...

High Added Value Without Additional Costs
The increasing use of granite in mechanical engineering is not so much due to the massive increase in the price of steel. Rather, it is because the added value for the machine tool achieved with a machine bed made of granite is possible at very little or no extra cost. This is proven by cost comparisons of well-known machine tool manufacturers in Germany and Europe.

The considerable gain in thermodynamic stability, vibration damping and long-term precision made possible by granite cannot be achieved with a cast iron or steel bed, or only at relatively high cost. For example, thermal errors can account for up to 75% of the total error of a machine, with compensation often attempted for by software – with moderate success. Due to its low thermal conductivity, granite is the better foundation for long-term precision.

With a tolerance of 1 μm, granite easily meets the flatness requirements according to DIN 876 for the degree of accuracy 00. With a value of 6 on the hardness scale 1 to 10, it is extremely hard, and with its specific weight of 2.8g/cm³ it almost reaches the value of aluminium. This also results in additional advantages such as higher feed rates, higher axis accelerations and an extension of the tool life for cutting machine tools. Thus, the change from a cast bed to a granite machine bed moves the machine tool in question into the high-end class in terms of precision and performance – at no extra cost.

Granite’s Improved Ecological Footprint
In contrast to materials such as steel or cast iron, natural stone does not have to be produced with a great deal of energy and using additives. Only relatively small amounts of energy are required for quarrying and surface treatment. This results in a superior ecological footprint, which even at the end of a machine’s life surpasses that of steel as a material. The granite bed can be the basis for a new machine or be used for completely different purposes such as shredding for road construction.

Nor are there any shortages of resources for granite. It is a deep rock formed from magma within the earth’s crust. It has ‘matured’ for millions of years and is available in very large quantities as a natural resource on almost all continents, including all of Europe.

Conclusion: The numerous demonstrable advantages of granite compared to steel or cast iron justify the increasing willingness of mechanical engineers to use this natural material as a foundation for high-precision, high-performance machine tools. Detailed information about granite properties, which are advantageous for machine tools and mechanical engineering, can be found in this further article.

A repeat measurement is a measurement of local flatness areas. The Repeat Measurement specification states that a measurement taken anywhere on the surface of a plate will repeat within the stated tolerance. Controlling local area flatness tighter than overall flatness guarantees a gradual change in surface flatness profile thereby minimizing local errors.

Most manufacturers, including imported brands, adhere to the Federal Specification of overall flatness tolerances but many overlook the repeat measurements. Many of the low value or budget plates available in the market today will not guarantee repeat measurements. A manufacturer who does not guarantee repeat measurements is NOT producing plates that meet the requirements of ASME B89.3.7-2013 or Federal Specification GGG-P-463c, or DIN 876, GB, JJS...

Both are critical to ensure a precision surface for accurate measurements. Flatness specification alone is not sufficient to guarantee measurement accuracy. Take as an example, a 36 X 48 Inspection Grade A surface plate, which meets ONLY the flatness specification of .000300". If the piece being checked bridges several peaks, and the gage being used is in a low spot, the measurement error could be the full tolerance in one area, 000300"! Actually, it can be much higher if the gage is resting on the slope of an incline.

Errors of .000600"-.000800" are possible, depending upon the severity of the slope, and the arm length of the gage being used. If this plate had a Repeat Measurement specification of .000050"F.I.R. then the measurement error would be less than .000050" regardless of where the measurement is taken on the plate. Another problem, which usually arises when an untrained technician attempts to resurface a plate on-site, is the use of Repeat Measurements alone to certify a plate.

The instruments that are used to verify repeatability are NOT designed to check overall flatness. When set to zero on a perfectly curved surface, they will continue to read zero, whether that surface is perfectly flat or perfectly concave or convex 1/2"! They simply verify the uniformity of the surface, not the flatness. Only a plate that meets both the flatness specification AND the repeat measurement specification truly meets the requirements of ASME B89.3.7-2013  or Federal Specification GGG-P-463c.

Ask us about or flatness specification and repeat measurement promise by calling +86 19969991659 or emailing INFO@ZHHIMG.COM

Yes, but they can only be guaranteed for a specific vertical temperature gradient. The effects of thermal expansion on the plate could easily cause a change in accuracy greater than the tolerance if there is a change in the gradient. In some cases, if the tolerance is tight enough, the heat absorbed from overhead lighting can cause enough of a gradient change over several hours.

Granite has a coefficient of thermal expansion of approximately .0000035 inches per inch per 1°F. As an example: A 36" x 48" x 8" surface plate has an accuracy of .000075" (1/2 of Grade AA) at a gradient of 0°F, the top and bottom are the same temperature. If the top of the plate warms up to the point where it is 1°F warmer than the bottom, the accuracy would change to .000275" convex ! Therefore, ordering a plate with a tolerance tighter than Laboratory Grade AA should only be considered if there is adequate climate control.

A surface plate should be supported at 3 points, ideally located 20% of the length in from the ends of the plate. Two supports should be located 20% of the width in from the long sides, and the remaining support should be centered. Only 3 points can rest solidly on anything but a precision surface.

The plate should be supported at these points during production, and it should be supported only at these three points while in use. Attempting to support the plate at more than three points will cause the plate to receive its support from various combinations of three points, which will not be the same 3 points on which it was supported during production. This will introduce errors as the plate deflects to conform to the new support arrangement. All zhhimg steel stands have support beams designed to line up with the proper support points.

If the plate is properly supported, precise leveling is only necessary if your application calls for it. Leveling is not necessary to maintain the accuracy of a properly supported plate.

Why Choose Granite for Machine Bases and Metrology Components?

The answer is 'yes' for almost every application. The advantages of granite include: No rust or corrosion, almost immune to warping, no compensating hump when nicked, longer wear life, smoother action, greater precision, virtually non-magnetic, low co-efficient of thermal expansion, and low maintenance cost.

Granite is a type of igneous rock quarried for its extreme strength, density, durability, and resistance to corrosion. But granite is also very versatile– it’s not just for squares and rectangles! In fact, Starrett Tru-Stone confidently works with granite components engineered in shapes, angles, and curves of all variations on a regular basis—with excellent outcomes.

Through our state of the art processing, cut surfaces can be exceptionally flat. These qualities make granite the ideal material to create custom-size and custom-design machine bases and metrology components. Granite is:

machineable
precisely flat when cut and finished
rust resistant
durable
long lasting
Granite components are also easy to clean. When creating custom designs, be sure to choose granite for its superior benefits.

STANDARDS / HIGH WEAR APPLICATIONS
The granite utilized by ZhongHui for our standard surface plate products has high quartz content, which provides greater resistance to wear and damage. Our Superior Black and Crystal Pink colors have low water absorption rates, minimizing the possibility of your precision gages rusting while setting on the plates. The colors of granite offered by ZhongHui result in less glare, which means less eyestrain for individuals using the plates. We have chosen our granite types while considering thermal expansion in an effort to keep this aspect minimal.

CUSTOM APPLICATIONS
When your application calls for a plate with custom shapes, threaded inserts, slots or other machining, you’ll want to select a material like Black Diabase. This natural material offers superior stiffness, excellent vibration dampening, and improved machinability.

Yes, if they are not too badly worn. Our factory setting and equipment allow the optimum conditions for proper plate calibration and rework if necessary. Generally, if a plate is within .001" of the required tolerance, it can be resurfaced on-site. If a plate is worn to the point where it is more than .001" out of tolerance, or if it is badly pitted or nicked, then it will need to be sent to the factory for grinding prior to relapping.

Great care should be exercised in selecting an on-site calibration and resurfacing technician. We urge you to use caution in selecting your calibration service. Ask for accreditation and verify the equipment that the technician will use has a National Inspection Institution traceable calibration. It takes many years to learn how to properly lap precision granite.

ZhongHui provides quick turn-around on calibrations performed in our factory. Send your plates in for calibration if possible. Your quality and reputation depend on the accuracy of your measurement instruments including surface plates!

Our black surface plates have a significantly higher density and are up to three times as stiff. Therefore, a plate made of the black does not need to be as thick as a granite plate of the same size to have equal or greater resistance to deflection. Reduced thickness means less weight and lower shipping costs.

Beware of others who use lower quality black granite in the same thickness. As stated above, properties of granite, like wood or metal, vary by material and color, and is not an accurate predictor of stiffness, hardness, or wear resistance. In fact, many types of black granite and diabase are very soft and not suitable for surface plate applications.

No. The specialized equipment and training necessary to rework these items requires that they be returned to the factory for calibration and rework.

Yes. Ceramic and granite have similar characteristics, and the methods used to calibrate and lap granite can be used with ceramic items as well. Ceramics are more difficult to lap than granite resulting in a higher cost.

Yes, provided that the inserts are recessed below the surface. If steel inserts are flush with, or above the surface plane, they must be spot-faced down before the plate can be lapped. If required, we can provide that service.

Yes. Steel inserts with the desired thread (English or metric) can be epoxy bonded into the plate at the desired locations. ZhongHui uses CNC machines to provide the tightest insert locations within +/- 0.005”. For less critical inserts, our locational tolerance for threaded inserts is ±.060". Other options include steel T-Bars and dovetail slots machined directly into the granite.

Inserts that are properly bonded using high strength epoxy and good workmanship will withstand a great deal of torsional and shear force. In a recent test, using 3/8"-16 threaded inserts, an independent testing laboratory measured the force required to pull an epoxy-bonded insert from a surface plate. Ten plates were tested. Out of these ten, in nine cases, the granite fractured first. The average load at the point of failure was 10,020 lbs. for gray granite and 12,310 lbs. for black. In the single case where an insert pulled free of the plate, the load at the point of failure was 12,990 lbs.! If a work piece forms a bridge across the insert and extreme torque is applied, it is possible to generate enough force to fracture the granite. Partially for this reason, ZhongHui gives guidelines for the maximum safe torque that can be applied the epoxy bonded inserts: https://www.zhhimg.com/standard-thread-inserts-product/

Yes, but only at our factory. At our plant, we can restore almost any plate to 'like-new' condition, usually for less than half the cost of replacing it. Damaged edges can be cosmetically patched, deep grooves, nicks, and pits can be ground out, and the attached supports can be replaced. In addition, we can modify your plate to increase its versatility by adding solid or threaded steel inserts and cutting slots or clamping lips, per your specifications.

Why Choose Granite?
Granite is a type of igneous rock formed in the Earth millions of years ago. The composition of igneous rock contained many minerals such as quartz that is extremely hard and wear-resistant. In addition to hardness and wear resistance granite has approximately half the coefficient of expansion as cast iron. As its volumetric weight is approximately one third that of cast iron, granite is easier to manoeuvre.

For machine bases and metrology components, black granite is the colour most used. Black granite has a higher percentage of quartz than other colours and is, therefore, the hardest wearing.

Granite is cost-effective, and cut surfaces can be exceptionally flat. Not only can it be hand lapped to achieve extremes of accuracy, but re-conditioning can be performed without moving the plate or table off-site. It is entirely a hand lapping operation and generally costs much less than re-conditioning a cast iron alternative.

These qualities make granite the ideal material to create custom-size and custom-design machine bases and metrology components such as the granite surface plate.

ZhongHui produces bespoke granite products that are created to support specific measurement requirements. These bespoke items vary from straight edges to tri squares. Due to the versatile nature of granite, the components can be produced to any size required; they are hard wearing and long-lasting.

Advantages of Granite Surface Plates
The importance of measuring on an even surface was established by British inventor Henry Maudsley in the 1800s. As a machine tool innovator, he determined that consistent production of parts required a solid surface for reliable measurements.

The industrial revolution created a demand for measuring surfaces, so engineering company Crown Windley created manufacturing standards. The standards for surface plates were first set by Crown in 1904 using metal. As the demand and cost for metal increased, alternative materials for the measuring surface were investigated.

In America, monument creator Wallace Herman established that black granite was an excellent surface plate material alternative to metal. As granite is non-magnetic and doesn’t rust, it soon became the preferred measuring surface.

A granite surface plate is an essential investment for laboratories and test facilities. A granite surface plate of 600 x 600 mm can be mounted on a support stand. The stands provide a working height of 34” (0.86m) with five adjustable points for levelling.

For reliable and consistent measurement results, a granite surface plate is crucial. As the surface is a smooth and stable plane, it enables instruments to be carefully manipulated.

The main advantages of granite surface plates are:

• Non-reflective
• Resistant to chemicals and corrosion
• Low coefficient of expansion compared with cart iron so less affected by temperature change
• Naturally rigid and hard-wearing
• The plane of the surface is unaffected if scratched
• Will not rust
• Non-magnetic
• Easy to clean and maintain
• Calibration and resurfacing can be done onsite
• Suitable for drilling for threaded support inserts
• High vibration damping

For many shops, inspection rooms and laboratories, precision granite surface plates are relied on as the basis for accurate measurement. Because every linear measurement depends on an accurate reference surface from which final dimensions are taken, surface plates provide the best reference plane for work inspection and layout prior to machining. They also are ideal bases for making height measurements and gaging surfaces. Further, a high degree of flatness, stability, overall quality and workmanship make them a good choice for mounting sophisticated mechanical, electronic and optical gaging systems. For any of these measurement processes, it is imperative to keep surface plates calibrated.

Repeat Measurements and Flatness
Both flatness and repeat measurements are critical to ensure a precision surface. Flatness can be considered as all points on the surface being contained within two parallel planes, the base plane and the roof plane. The measurement of distance between the planes is the overall flatness of the surface. This flatness measurement commonly carries a tolerance and may include a grade designation.

The flatness tolerances for three standard grades are defined in the federal specification as determined by the following formula:
Laboratory Grade AA = (40 + diagonal² / 25) x 0.000001 inch (unilateral)
Inspection Grade A = Laboratory Grade AA x 2
Tool Room Grade B = Laboratory Grade AA x 4

In addition to flatness, repeatability must be ensured. A repeat measurement is a measurement of local flatness areas. It is a measurement taken anywhere on the surface of a plate that will repeat within the stated tolerance. Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.

To ensure a surface plate meets both the flatness and repeat measurement specifications, manufacturers of granite surface plates should use Federal Specification GGG-P-463c as a basis for their specifications. This standard addresses repeat measurement accuracy, material properties of surface plate granites, surface finish, support point location, stiffness, acceptable methods of inspection and installation of threaded inserts.

Before a surface plate has worn beyond specification for overall flatness, it will show worn or wavy posts. Monthly inspection for repeat measurement errors using a repeat reading gage will identify wear spots. A repeat reading gage is a high-precision instrument that detects local error and can be displayed on a high magnification electronic amplifier.

Checking Plate Accuracy
By following a few simple guidelines, an investment in a granite surface plate should last for many years. Depending on plate usage, shop environment and required accuracy, frequency of checking the surface plate accuracy varies. A general rule of thumb is for a new plate to receive a full recalibration within one year of purchase. If the plate is used frequently, it is advisable to shorten this interval to six months.

Before a surface plate has worn beyond specification for overall flatness, it will show worn or wavy posts. Monthly inspection for repeat measurement errors using a repeat reading gage will identify wear spots. A repeat reading gage is a high-precision instrument that detects local error and can be displayed on a high magnification electronic amplifier.

An effective inspection program should include regular checks with an autocollimator, providing actual calibration of overall flatness traceable to National Institute of Standards and Technology (NIST). Comprehensive calibration by the manufacturer or an independent company is necessary from time to time.

Variations Between Calibrations
In some cases, there are variations between surface plate calibrations. Sometimes factors such as surface change resulting from wear, incorrect use of inspection equipment or use of noncalibrated equipment can account for these variations. The two most common factors, however, are temperature and support.

One of the most important variables is temperature. For instance, the surface might have been washed with a hot or cold solution prior to calibration and not allowed sufficient time to normalize. Other causes of temperature change include drafts of cold or hot air, direct sunlight, overhead lighting or other sources of radiant heat on the surface of the plate.

There also can be variations in the vertical temperature gradient between winter and summer. In some cases, the plate is not allowed sufficient time to normalize after shipment. It is a good idea to record the vertical gradient temperature at the time the calibration is performed.

Another common cause for calibration variation is a plate that is improperly supported. A surface plate should be supported at three points, ideally located 20% of the length in from the ends of the plate. Two supports should be located 20% of the width in from the long sides, and the remaining support should be centered.

Only three points can rest solidly on anything but a precision surface. Attempting to support the plate at more than three points will cause the plate to receive its support from various combinations of three points, which will not be the same three points on which it was supported during production. This will introduce errors as the plate deflects to conform to the new support arrangement. Consider using steel stands with support beams designed to line up with the proper support points. Stands for this purpose are generally available from the surface plate manufacturer.

If the plate is properly supported, precise leveling is only necessary if an application specifies it. Leveling is not necessary to maintain the accuracy of a properly supported plate.

It is important to keep the plate clean. Airborne abrasive dust is usually the greatest source of wear and tear on a plate, as it tends to embed in workpieces and the contact surfaces of gages. Cover plates to protect them from dust and damage. Wear life can be extended by covering the plate when not in use.

Extend Plate Life
Following a few guidelines will reduce wear on a granite surface plate and ultimately, extend its life.

First, it is important to keep the plate clean. Airborne abrasive dust is usually the greatest source of wear and tear on a plate, as it tends to embed in workpieces and the contact surfaces of gages.

It also is important to cover plates to protect it from dust and damage. Wear life can be extended by covering the plate when not in use.

Rotate the plate periodically so that a single area does not receive excessive use. Also, it is recommended to replace steel contact pads on gaging with carbide pads.

Avoid setting food or soft drinks on the plate. Many soft drinks contain either carbonic or phosphoric acid, which can dissolve the softer minerals and leave small pits in the surface.

Where to Relap
When a granite surface plate needs re-surfacing, consider whether to have this service performed on-site or at the calibration facility. It is always preferable to have the plate relapped at the factory or a dedicated facility. If, however, the plate is not too badly worn, generally within 0.001 inch of the required tolerance, it can be resurfaced on-site. If a plate is worn to the point where it is more than 0.001 inch out of tolerance, or if it is badly pitted or nicked, then it should be sent to the factory for grinding prior to relapping.

A calibration facility has the equipment and factory setting providing the optimum conditions for proper plate calibration and rework if necessary.

Great care should be exercised in selecting an on-site calibration and resurfacing technician. Ask for accreditation and verify the equipment that the technician will use has a NIST-traceable calibration. Experience also is an important factor, as it takes many years to learn how to correctly lap precision granite.

Critical measurements start with a precision granite surface plate as a baseline. By ensuring a reliable reference by using a properly calibrated surface plate, manufacturers have one of the essential tools for reliable measurements and better quality parts.

Checklist for Calibration Variations

1. The surface was washed with a hot or cold solution prior to calibration and was not allowed sufficient time to normalize.
2. The plate is improperly supported.
3. Temperature change.
4. Drafts.
5. Direct sunlight or other radiant heat on the surface of the plate. Be sure that overhead lighting is not heating the surface.
6. Variations in the vertical temperature gradient between winter and summer. If at all possible, know the vertical gradient temperature at the time the calibration is performed.
7. Plate not allowed sufficient time to normalize after shipment.
8. Improper use of inspection equipment or use of noncalibrated equipment.
9. Surface change resulting from wear.

Tech Tips
Because every linear measurement depends on an accurate reference surface from which final dimensions are taken, surface plates provide the best reference plane for work inspection and layout prior to machining.

Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.