Granite bụ ụdị nkume igneous e gwuru n'ihi ike ya dị oke elu, njupụta ya, ogologo ya, na iguzogide nchara ya. Mana granite dịkwa ọtụtụ ihe - ọ bụghị naanị maka square na rectangles! N'ezie, anyị ji obi ike na-arụ ọrụ na ihe ndị e ji granite rụọ n'ụdị, akụkụ, na agba nke ụdị dị iche iche mgbe niile - yana nsonaazụ dị mma.
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:
■ enwere ike iji igwe rụọ ọrụ
■ nke dị larịị kpọmkwem mgbe e bepụrụ ya ma mechaa ya
■ anaghị eguzogide nchara
■ siri ike
■ na-adịte aka
Ihe ndị e ji granite mee dịkwa mfe ihicha. Mgbe ị na-emepụta ihe pụrụ iche, jide n'aka na ị ga-ahọrọ granite maka uru ya dị elu.

Ọkwa / Ngwa Ndị Dị Elu
Granite nke ZHHIMG ji eme ngwaahịa efere elu anyị nwere nnukwu ọdịnaya quartz, nke na-enye ike iguzogide iyi na mmebi. Agba ojii anyị dị elu nwere obere ọsọ mmiri na-amịkọrọ, na-ebelata ohere nke nha ziri ezi gị na-agba nchara mgbe ị na-etinye na efere. Agba nke granite nke ZHHIMG na-enye na-eme ka anya ghara ịcha nke ọma, nke pụtara na ndị na-eji efere ahụ anaghị enwe ike ịcha anya. Anyị ahọrọla ụdị granite anyị ebe anyị na-atụle mmụba okpomọkụ iji mee ka akụkụ a dị obere.

CUSTOM APPLICATIONS
Mgbe ngwa gị chọrọ efere nwere ọdịdị pụrụ iche, ihe ntinye eriri, oghere ma ọ bụ igwe ndị ọzọ, ị ga-achọ ịhọrọ ihe dị ka Black Jinan Black. Ihe okike a na-enye ike dị elu, mbelata mkpọtụ dị mma, na ikike igwe ka mma.

Ọ dị mkpa ịmara na agba naanị abụghị ihe na-egosi àgwà anụ ahụ nke nkume ahụ. N'ozuzu, agba granite metụtara kpọmkwem na ọnụnọ ma ọ bụ enweghị mineral, nke nwere ike ọ gaghị enwe mmetụta ọ bụla na àgwà ndị na-eme ka efere elu dị mma. E nwere granite pink, isi awọ, na oji nke dị mma maka efere elu, yana granite ojii, isi awọ, na pink nke na-adịghị mma maka ojiji ziri ezi. Ihe ndị dị mkpa nke granite, dịka ha si metụta ojiji ya dị ka ihe efere elu, enweghị ihe jikọrọ ya na agba, ha bụkwa ndị a:
■ Ike (nkwụsị n'okpuru ibu - Modulus of Elasticity gosiri)
■ Ike siri ike
■ Njupụta
■ Mgbochi iyi
■ Ịkwụsi ike
■ Ntụpọ

Anyị anwalela ọtụtụ ihe granite ma tụnyere ihe ndị a. N'ikpeazụ, anyị nwetara nsonaazụ ya, granite ojii Jinan bụ ihe kacha mma anyị maara. Granite ojii Indian na granite ndịda Africa yiri Jinan Black Granite, mana ihe onwunwe ha erughị Jinan Black Granite. ZHHIMG ga-anọgide na-achọ ihe granite karịa n'ụwa ma tụnyere ihe onwunwe ha.

Iji kwuo maka granite nke dabara adaba maka ọrụ gị, biko kpọtụrụ anyịinfo@zhhimg.com.

Ndị nrụpụta dị iche iche na-eji ọkọlọtọ dị iche iche. E nwere ọtụtụ ọkọlọtọ n'ụwa.
DIN Standard, ASME B89.3.7-2013 ma ọ bụ Federal Specification GGG-P-463c (Granite Surface Plates) na ihe ndị ọzọ dịka ntọala maka nkọwapụta ha.

Anyị nwekwara ike imepụta efere nyocha granite dịka ihe ị chọrọ si dị. Nnọọ ka ịkpọtụrụ anyị ma ọ bụrụ na ịchọrọ ịmatakwu gbasara ụkpụrụ ndị ọzọ.

A pụrụ iwere ịdị larịị dị ka isi ihe niile dị n'elu ahụ dị n'ime oghere abụọ yiri ibe ha, nke bụ ntọala na nke dị n'elu ụlọ. Ntụle anya dị n'etiti oghere ndị ahụ bụ ịdị larịị zuru oke nke elu ahụ. Ntụle ịdị larịị a na-enwekarị ndidi ma nwee ike ịgụnye aha ọkwa.

Dịka ọmụmaatụ, a na-akọwa nnabata flatness maka akara ọkọlọtọ atọ na nkọwapụta gọọmentị etiti dịka usoro a si ekpebi:
■ Ọkwa Ụlọ Nyocha AA = (40 + akụkụ anọ nke diagonal/25) x .000001" (otu akụkụ)
■ Nnyocha Ọkwa A = Ọkwa Ụlọ Nyocha AA x 2
■ Ụlọ Ngwaọrụ Klas B = Klas AA nke Ụlọ Nyocha x 4.

Maka efere elu ọkọlọtọ, anyị na-ekwe nkwa na a ga-anabata nha nha nke gafere ihe achọrọ na nkọwapụta a. Na mgbakwunye na nha nha, ASME B89.3.7-2013 & Federal Specification GGG-P-463c na-aza ajụjụ ndị gụnyere: izi ezi nha ugboro ugboro, ihe onwunwe nke granite efere elu, imecha elu, ebe nkwado, ike, ụzọ nyocha a na-anabata, ntinye nke ihe ntinye eriri, wdg.

Efere elu granite ZHHIMG na efere nyocha granite na-emezu ma ọ bụ gafere ihe niile achọrọ na nkọwapụta a. Ugbu a, enweghị nkọwapụta akọwapụtara maka efere akụkụ granite, parallels, ma ọ bụ master squares.

Ị nwekwara ike ịchọta usoro maka ọkọlọtọ ndị ọzọ naBUDATA.

Nke mbụ, ọ dị mkpa idobe efere ahụ ọcha. Uzuzu a na-eji n'ikuku na-abụkarị isi iyi kachasị njọ nke mmebi na mgbawa n'elu efere, ebe ọ na-abụkarị itinye ihe ndị a na-arụ ọrụ na ebe ndị a na-emetụ aka na gages. Nke abụọ, kpuchie efere gị iji chebe ya pụọ ​​na uzuzu na mmebi. Enwere ike ịgbatị ndụ iyi site na ikpuchi efere ahụ mgbe a na-ejighị ya, site n'ịtụgharị efere ahụ mgbe niile ka otu ebe ghara iji ya mee ihe gabiga ókè, nakwa site n'iji ihe mkpuchi carbide dochie ihe mkpuchi ígwè na nha. Ọzọkwa, zere itinye nri ma ọ bụ ihe ọṅụṅụ dị nro n'elu efere ahụ. Rịba ama na ọtụtụ ihe ọṅụṅụ dị nro nwere ma carbonic ma ọ bụ phosphoric acid, nke nwere ike ịgbaze mineral ndị dị nro ma hapụ obere olulu n'elu.

Nke a dabere n'otú e si eji efere ahụ eme ihe. Ọ bụrụ na o kwere mee, anyị na-akwado ka e hichaa efere ahụ na mbido ụbọchị (ma ọ bụ ọrụ) nakwa na njedebe ya. Ọ bụrụ na efere ahụ emerụọ, ọkachasị na mmiri mmanụ ma ọ bụ ihe na-arapara arapara, o yikarịrị ka a ga-ehicha ya ozugbo.

Jiri mmiri mmiri ma ọ bụ ihe nhicha efere ZHHIMG na-ehicha efere ahụ mgbe niile. Nhọrọ nke ihe ngwọta nhicha dị mkpa. Ọ bụrụ na ejiri ihe mgbaze na-agbanwe agbanwe (acetone, lacquer thinner, alcohol, wdg) evaporation ga-eme ka elu ahụ jụọ oyi, ma gbagọọ ya. N'okwu a, ọ dị mkpa ikwe ka efere ahụ mee ka ọ dị mma tupu e jiri ya ma ọ bụghị ya, njehie nha ga-eme.

Oge a ga-eji mee ka efere ahụ dịghachi mma ga-adị iche dabere na nha efere ahụ, na oke oyi ahụ. Otu awa kwesịrị izu oke maka obere efere. Enwere ike ịchọ awa abụọ maka nnukwu efere. Ọ bụrụ na ejiri ihe nhicha mmiri mee ihe, a ga-enwekwa ụfọdụ oyi na-ekupụ ikuku.

Efere ahụ ga-ejidekwa mmiri ahụ, nke a nwekwara ike ime ka akụkụ ígwè ghara ịcha nchara. Ụfọdụ ndị na-ehicha ihe ga-ahapụkwa ihe fọdụrụ mgbe ha kpọrọ nkụ, nke ga-adọta uzuzu ikuku, ma mee ka ọ na-emebi emebi, kama ibelata ya.

Nke a dabere na ojiji efere na gburugburu ebe obibi. Anyị na-akwado ka e mee mgbanwe zuru oke na efere ọhụrụ ma ọ bụ ihe mgbakwunye granite ziri ezi n'ime otu afọ nke ịzụrụ ya. Ọ bụrụ na efere elu granite ahụ ga-adị oke ojiji, ọ ga-adị mma ka e mee ka oge a dị mkpụmkpụ ruo ọnwa isii. Nnyocha kwa ọnwa maka njehie nha ugboro ugboro site na iji ọkwa eletrọniki, ma ọ bụ ngwaọrụ yiri ya, ga-egosi ntụpọ ọ bụla na-etolite ma na-ewe naanị nkeji ole na ole iji mee ya. Mgbe achọpụtachara nsonaazụ nke nhazi mbụ ahụ, enwere ike ịgbatị ma ọ bụ belata oge nhazi dịka sistemụ mma ime gị kwere ma ọ bụ chọọ.

Anyị nwere ike inye ọrụ iji nyere gị aka inyocha ma hazie efere elu granite gị.

E nwere ọtụtụ ihe nwere ike ịkpata mgbanwe dị iche iche n'etiti nhazi:

• A sachara elu ahụ na mmiri ọkụ ma ọ bụ oyi tupu e mee nhazi ya, e kweghịkwa ka o ruo oge zuru oke iji mee ka ọ dị mma.
• A na-akwado efere ahụ nke ọma
• Mgbanwe okpomọkụ
• Edemede
• Anwụ kpọmkwem ma ọ bụ okpomọkụ ọzọ na-enwu enwu n'elu efere ahụ. Hụ na ọkụ dị n'elu anaghị ekpo ọkụ n'elu ya.
• Mgbanwe dị na mgbanwe okpomọkụ kwụ ọtọ n'etiti oge oyi na oge okpomọkụ (Ọ bụrụ na ọ ga-ekwe omume, mara okpomọkụ mgbanwe kwụ ọtọ n'oge a na-eme nhazi ahụ.)
• E kweghị ka efere ahụ nwee oge zuru oke iji mee ka ọ dị mma mgbe ebusịrị ya
• Iji ngwa nyocha eme ihe n'ụzọ na-ekwesịghị ekwesị ma ọ bụ iji ngwa ndị a na-anaghị ahazi
• Mgbanwe elu sitere na iyi

Kedu ụdị oghere dị na granite ziri ezi?

Oghere dị na ihe mejupụtara Granite nkenke

Maka ọtụtụ ụlọ ọrụ mmepụta ihe, ụlọ nyocha na ụlọ nyocha, a na-adabere na efere elu granite ziri ezi dị ka ntọala maka nha ziri ezi. Ebe ọ bụ na nha ọ bụla dabere na elu ntụaka ziri ezi nke a na-esi na ya wepụta nha ikpeazụ, efere elu na-enye ntụaka kacha mma maka nyocha na nhazi ọrụ tupu arụ ọrụ. Ha bụkwa ntọala zuru oke maka ime nha elu na elu nlele. Ọzọkwa, oke dị larịị, nkwụsi ike, ịdị mma zuru oke na ọrụ aka na-eme ka ha bụrụ ezigbo nhọrọ maka itinye sistemụ igwe, eletrọnịkị na optical dị elu. Maka usoro nha ọ bụla a, ọ dị mkpa idobe efere elu na nhazi.

Repeat Measurements and Flatness

Ma nha dị larịị ma nha ugboro ugboro dị oke mkpa iji hụ na elu ahụ dị mma. Enwere ike ịtụle ịdị larịị dị ka isi ihe niile dị n'elu ahụ dị n'ime oghere abụọ yiri ibe ha, nke bụ ntọala na nke dị n'elu ụlọ. Ntụle anya dị n'etiti oghere ndị ahụ bụ ịdị larịị zuru oke nke elu ahụ. Ntụle ịdị larịị a na-enwekarị ndidi ma nwee ike ịgụnye aha ọkwa.

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

DIN Standard, GB Standard, ASME Standard, JJS Standard... obodo dị iche iche nwere ọnọdụ dị iche...

Nkọwa ndị ọzọ gbasara ọkọlọtọ.

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.

Iji hụ na efere elu na-emezu ma nha nha dị larịị ma nke ugboro ugboro, ndị na-emepụta efere elu granite kwesịrị iji Nkọwapụta Federal GGG-P-463c dị ka ntọala maka nkọwapụta ha. Ọkọlọtọ a na-eleba anya na izi ezi nha ugboro ugboro, ihe onwunwe nke granite efere elu, imecha elu, ebe nkwado, ike siri ike, ụzọ a na-anabata nke inyocha na itinye ihe ntinye eriri.

Checking Plate Accuracy

Site n'ịgbaso ntuziaka ole na ole dị mfe, itinye ego na efere elu granite kwesịrị ịdịru ọtụtụ afọ. Dabere na ojiji efere, gburugburu ụlọ ahịa na izi ezi achọrọ, ugboro ole a na-enyocha izi ezi nke efere elu dị iche iche. Iwu izugbe bụ ka efere ọhụrụ nweta nhazi zuru oke n'ime otu afọ nke ịzụrụ ya. Ọ bụrụ na a na-eji efere ahụ ugboro ugboro, ọ dị mma ka e belata oge a ruo ọnwa isii.

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

N'ọnọdụ ụfọdụ, enwere mgbanwe dị iche iche n'etiti nhazi efere elu. Mgbe ụfọdụ, ihe dịka mgbanwe elu sitere na iyi, ojiji na-ezighi ezi nke ngwa nyocha ma ọ bụ ojiji nke akụrụngwa na-anaghị agbanwe agbanwe nwere ike ịkọwa mgbanwe ndị a. Agbanyeghị, ihe abụọ kachasị akpata ya bụ okpomọkụ na nkwado.

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

Ịgbaso ntuziaka ole na ole ga-ebelata iyi na efere elu granite ma mechaa mee ka ọ dịte aka.

Nke mbụ, ọ dị mkpa idobe efere ahụ ọcha. Uzuzu a na-eji ikuku eme ihe na-abụkarị ihe kachasị emebi emebi na efere, ebe ọ na-abanyekarị n'ime ihe ndị a na-arụ ọrụ na ebe ndị a na-ahụ maka ihe nlele.

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.

Na-atụgharị efere ahụ mgbe niile ka e wee ghara iji otu ebe eme ihe gabiga ókè. A na-atụkwa aro ka e jiri ihe mkpuchi carbide dochie ihe mkpuchi ígwè na-akpọtụrụ na nha nha.

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

Ọ bụrụ na e nwere efere granite dị mkpa ka e tinyegharịa ya, tụlee ma a ga-arụ ọrụ a n'ebe a na-arụzi ya ma ọ bụ n'ebe a na-ahazi ya. Ọ ka mma ka e jiri efere ahụ tụgharịa ya n'ụlọ ọrụ mmepụta ihe ma ọ bụ ebe a na-arụzi ya. Agbanyeghị, ọ bụrụ na efere ahụ adịghị emebi nke ukwuu, nke na-adịkarị n'ime 0.001 inch nke ike achọrọ, enwere ike ịpụgharị ya ọzọ n'ebe ahụ. Ọ bụrụ na e jiri efere ahụ mee ihe ruo n'ókè nke na ọ karịrị 0.001 inch nke ike ịnagide ya, ma ọ bụ ọ bụrụ na e ji ájá ma ọ bụ ọkpọkọ mee ya nke ọma, mgbe ahụ, a ga-eziga ya n'ụlọ ọrụ mmepụta ihe maka ịgweri ya tupu e jiri ya mee ihe ọzọ.

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

A ga-akpachara anya nke ọma n'ịhọrọ onye na-ahụ maka nhazi na imegharị ihe n'ebe ahụ. Rịọ maka asambodo ma hụ na akụrụngwa onye ọrụ ga-eji nwere nhazi a pụrụ ịchọta. Ahụmịhe bụkwa ihe dị mkpa, ebe ọ na-ewe ọtụtụ afọ iji mụta otu esi agba granite ziri ezi.

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. E ji ihe na-ekpo ọkụ ma ọ bụ oyi saa elu ahụ tupu e mee nhazi ya, e kweghịkwa ka o ruo oge zuru oke iji mee ka ọ dị mma.

2. E jighị efere ahụ kwado ya nke ọma.

3. Mgbanwe okpomọkụ.

4. Edemede.

5. Anwụ kpọmkwem ma ọ bụ okpomọkụ ọzọ na-enwu enwu n'elu efere ahụ. Jide n'aka na ọkụ dị n'elu anaghị ekpo ọkụ n'elu ya.

6. Mgbanwe dị na mgbanwe okpomọkụ kwụ ọtọ n'etiti oge oyi na oge okpomọkụ. Ọ bụrụ na ọ ga-ekwe omume, mara okpomọkụ mgbanwe kwụ ọtọ n'oge a na-eme nhazi ahụ.

7. E kweghị ka efere ahụ mee ka ọ dị mma mgbe ebusịrị ya.

8. Iji ngwa nyocha eme ihe n'ụzọ na-ekwesịghị ekwesị ma ọ bụ iji ngwa ndị a na-anaghị ahazi eme ihe.

9. Mgbanwe elu nke na-esi na mmebi pụta.

Tech Tips

• Ebe ọ bụ na nha nha ọ bụla dabere na elu ntụaka ziri ezi nke e si na ya wepụta akụkụ ikpeazụ, efere elu na-enye usoro ntụaka kacha mma maka inyocha na nhazi ọrụ tupu arụ ọrụ.
• Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.
• Mmemme nyocha dị irè kwesịrị ịgụnye nyocha mgbe niile na ihe na-eme ka a na-akpọ autocollimator, nke na-enye nhazi nke larịị zuru oke nke National Inspection Authority nwere ike ịchọta.

N'ime ihe ndị mejupụtara granite, ihe karịrị 90% bụ feldspar na quartz, nke feldspar kacha. Feldspar na-abụkarị ọcha, isi awọ, na-acha ọbara ọbara, quartz na-abụkarịkwa ọcha isi awọ ma ọ bụ isi awọ, nke bụ agba isi awọ nke granite. Feldspar na quartz bụ mineral siri ike, ọ na-esikwa ike ịkwaga na mma ígwè. Banyere ntụpọ gbara ọchịchịrị na granite, ọkachasị mica ojii, enwere ụfọdụ mineral ndị ọzọ. Ọ bụ ezie na biotite dị nro, ikike ya iguzogide nrụgide adịghị ike, n'otu oge ahụ ha nwere obere ego na granite, ọtụtụ mgbe ihe na-erughị 10%. Nke a bụ ọnọdụ ihe nke granite siri ike karịsịa.

Ihe ọzọ mere granite ji sie ike bụ na ihe ndị dị n'ime ya na-ejikọta onwe ha nke ọma ma na-abanye n'ime ibe ha. Oghere ndị ahụ na-abụkarị ihe na-erughị 1% nke olu nkume ahụ dum. Nke a na-enye granite ikike iguzogide nrụgide siri ike ma mmiri anaghị abanye ya ngwa ngwa.

A na-eji nkume mee ihe ndị dị na granite, ha enweghị nchara, ha anaghị eguzogide acid na alkali, ha anaghị eguzogide iyi nke ọma, ha anaghịkwa echekwa ogologo oge. A na-ejikarị ihe ndị dị na granite eme ihe n'ime ngwaọrụ nke ụlọ ọrụ igwe. Ya mere, a na-akpọ ha ihe ndị dị na granite ma ọ bụ ihe ndị dị na granite. Àgwà nke ihe ndị dị na granite ziri ezi bụ otu ihe ahụ dị ka nke nyiwe granite. Okwu Mmalite maka ngwaọrụ na nha nke ihe ndị dị na granite ziri ezi: Ịrụ ọrụ nke ọma na teknụzụ igwe bụ ntụziaka mmepe dị mkpa maka ụlọ ọrụ mmepụta igwe, ha aghọọla ihe ngosi dị mkpa iji tụọ ọkwa teknụzụ dị elu. Mmepe nke teknụzụ kachasị elu na ụlọ ọrụ nchekwa enweghị ike ikewapụ ya na igwe nhazi ziri ezi na teknụzụ igwe nhazi obere. Enwere ike ịmịnye ihe ndị dị na granite nke ọma na nha, na-enweghị nkwụsị. Nha elu ọrụ, ihe ndị dị na ya anaghị emetụta izi ezi nha. A chọrọ ka e mepụta ma mepụta ihe ndị dị na granite dịka ihe achọrọ si dị.

Ubi ngwa:

Dịka anyị niile maara, ọtụtụ igwe na akụrụngwa na-ahọrọ ihe ndị e ji granite mee nke ọma.

A na-eji ihe ndị dị na granite eme ihe maka mmegharị ike, moto linear, cmm, cnc, igwe laser...

Nnọọ kpọtụrụ anyị maka ozi ndị ọzọ.

E ji granite Jinan Black dị elu mee ngwaọrụ nha granite na ihe ndị ọzọ e ji arụ ọrụ granite. N'ihi oke nhazi ha, ogologo oge ha, ezigbo nkwụsi ike na iguzogide nchara, a na-ejikarị ha eme ihe n'inyocha ngwaahịa nke ụlọ ọrụ ọgbara ọhụrụ na mpaghara sayensị dịka oghere ikuku igwe na nyocha sayensị.

Uru

----Ugboro abụọ siri ike dị ka ígwè a kpụrụ akpụ;

----Mgbanwe kacha nta nke nha bụ n'ihi mgbanwe nke okpomọkụ;

----Enweghị nsogbu, yabụ na ọrụ agaghị akwụsị akwụsị;

----Enweghị ihe ọ bụla na-esi na burrs ma ọ bụ protrusion pụta n'ihi nhazi ọka dị mma na obere rapara, nke na-eme ka ọ dị larịị ruo ogologo oge ọrụ ma ghara imebi akụkụ ma ọ bụ ngwa ndị ọzọ;

----Arụ ọrụ na-enweghị nsogbu maka iji ihe magnetik;

----Ọ na-adịte aka ma ghara ịcha nchara, nke na-eme ka ọ ghara ịdị ọnụ ala n'ihi mmezi ya.

A na-eji efere granite ndị a eme ihe nke ọma ruo n'ókè dị elu nke ịdị larịị iji nweta izi ezi, a na-ejikwa ha dịka ntọala maka ịkwanye sistemụ igwe, eletrọnịkị na optical dị elu.

Ụfọdụ ihe pụrụ iche nke efere elu granite:

Ịdị n'otu n'ime ike;

Ọnọdụ dị n'okpuru ibu ziri ezi;

Ihe Na-amịkọrọ Mmiri;

Mfe Ịsacha;

Ihe mgbochi mkpuchi;

Obere Porosity;

Anaghị emerụ ahụ;

Na-abụghị Magnetik

Uru nke 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.