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| Q1: |
What kind of Tools does Kyocera handle and what are they for ? |
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| A1: |
Kyocera provides indexable cutting tool inserts under the tradename CERATIP with grades of ceramic, cermet, coated tool, solid carbide, CBN and PCD tools, as well as toolholders to attach those inserts to the machine tools.
From these product lineup, almost all of the materials used at metalworking, such as cast irons, steels, alloy steels, special steels like stainless steel and non-ferrous metals like aluminum and copper are the objects to be machined by CERATIP. |
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| Q2: |
There are two types of coating, CVD and PVD. How do you use properly ? |
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| A2: |
CVD means Chemical Vapor Deposition, and PVD means Physical Vapor Deposition. Their characteristics are as follows.
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PVD |
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Equal Coating for All Surface |
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Suitable for Mass Production |
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Substrate's Bending Strength Decreases |
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Substrate may Deleriorate |
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Substrate may Soften |
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Not Suitable for Mass Production |
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Substrate's Bending Strength does not Decrease |
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No Substrate's Deterioration |
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Good for Anti-Chipping Performance |
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| Coating Temp. 900~1100°C |
Coating Temp. 400~600°C |
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There's no significant limit on the application between the two and they are used considering their characteristics respectively. Generally speaking, CVD tool is popular in turning and PVD tool is popular in milling applications.
Kyocera CERATIP's Product Lineup
| CVD Coat --- |
CR7015, CR7025, CR9025, CA225, CA5025, CA6015
(All of substrates are carbide) |
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| PVD Coat --- |
PR510, PR610, PR630, PR660, PR730, PR905, PR915, PR930
(Substrates of PR series are carbide)
PV30, PV60, PV90
(Substrates of PV series are cermet) |
For the details, please refer to Kyocera Catalog |
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| Q3: |
Why are there various chipbreaker types ? |
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| A3: |
The chip control is a very important factor, as it is said that how to control chips is the most important point in metalworking. Chipbreaker is a groove or projection or those combination on the cutting insert to control chips coming out of the workpiece during the cutting operation.
The purpose of chipbreaker is as follows.
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Cuts chips short and controls their length and direction |
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Reduces cutting resistance and brings sharp cutting performance |
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Extends the tool life longer |
If there's no chipbreaker, chips come out from the cutting edge straight and the machine operator is in dangerous conditions or chips are entangled with the machine hard, and the productivity greatly reduces. Chip's evacuation way changes, depending on the workpiece material or the cutting conditions, and various geometries of chipbreaker have been developed in order to control chips well at any cutting conditions.
Kyocera provides various types of molded chipbreaker that is prepared on the surface of the insert by molding, and the ground chipbreaker that is ground on the insert surface, as well as the attachment type chipbreaker for ceramic insert.
Depending on the application and cutting conditions, customers can select the most suitable chipbreaker geometries.
For the details, please refer to Kyocera catalog. |
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| Q4: |
Are there any good ways to improve surface roughness at turning operation ? |
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| A4: |
The most well-known way is to make the feed rate (f) smaller and make the insert's corner radius (R) bigger. The theoretical surface roughness is formulated as Ry=fxf /8R x 1000. Then, by making (f) small and (R) big, Ry becomes small value.
However, if the machining conditions do not allow such changes, the higher cutting speed leads better surface roughness. Because the high speed machining prevents the built-up edge. |
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| Q5: |
What is the way to improve the chip control at turning operation ? |
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| A5: |
Firstly, confirm if the suitable chipbreaker is used at the workpiece and also confirm the cutting conditions. The cutting conditions may have changed, compared with the ones at the original selection.
If the chipbreaker is selected correctly and the cutting conditions such as feed rate and the depth of cut are also correct, decreasing the cutting speed leads the chip control improvement. Because by decreasing the cutting speed, chip thickness becomes bigger and chips become broken easily. |
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| Q6: |
At grooving operation, is there any effective way to obtain the shiny surface at the groove bottom ? |
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| A6: |
The available effective ways to have the shiny surface at the groove bottom are as follows.
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Increase the cutting speed |
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Apply light honing to the cutting edge by hand lapper |
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Use dwell-motion (to stop the tool feed for an instant at the groove bottom) |
The reason is, 1) increasing cutting speed prevents the built-up edge, 2) rather round edge makes shiny surface compared with really sharp edge, and 3) by dwelling the tool, the cutting edge rubs the groove bottom and it makes shiny surface. |
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| Q7: |
At SUS304 stainless steel machining, decreasing the depth of cut and feed rate for the less load to the cutting edge made the tool life shorter, on the contrary. Why ? |
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| A7: |
As the specific characteristic of stainless steels, work hardening phenomenon happens to the surface of stainless steel soon after it was machined.
Then, if the depth of cut or the feed rate is too small, the cutting edge cuts the hardened part and the tool life becomes shorter since the cutting edge is damaged soon.
Stainless steel becomes hard up to the depth of 0.1 to 0.2 mm from the surface. Then making the depth of cut more than 0.5 mm and feed rate about 0.2 mm/rev. is recommended. |
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| Q8: |
How can Aluminum be machined well ? |
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| A8: |
At Aluminum machining, it is very important to make chip evacuation good and prevent the Aluminum's adhesion to the cutting edge. Therefore the sharp edge for the sharp cutting performance, higher rake angle and high speed & high feed rate machining are recommended. When turning, it is effective to use water based coolant to wash chips away and prevent adhesion. When milling, use air to blow off chips. It is also very effective to apply mirror polishing to the rake face and relief face of the cutting tool. |
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