鉸孔和鑽孔、擴孔一樣都是由刀具本身的尺寸來保證被加工孔的尺寸的，但鉸孔的品9質要高得多。鉸孔餘量對鉸孔品質的影響很大，餘量太大，鉸刀的負荷大，切削刃很快被磨鈍，不易獲得光潔的加工表面，尺寸公差也不易保證；餘量太小，不能去掉上工序留下的刀痕，自然也就沒有改善孔加工品質的作用。一般粗鉸餘量取為0.35－0.15mm，精鉸取為0.15－0.05mm。鉸孔尺寸精度一般為IT9－IT7級，表面粗糙度Ra一般為3.2－0.8μm。
- 12月 23 週一 201312:18
孔加工精度
鉸孔和鑽孔、擴孔一樣都是由刀具本身的尺寸來保證被加工孔的尺寸的，但鉸孔的品9質要高得多。鉸孔餘量對鉸孔品質的影響很大，餘量太大，鉸刀的負荷大，切削刃很快被磨鈍，不易獲得光潔的加工表面，尺寸公差也不易保證；餘量太小，不能去掉上工序留下的刀痕，自然也就沒有改善孔加工品質的作用。一般粗鉸餘量取為0.35－0.15mm，精鉸取為0.15－0.05mm。鉸孔尺寸精度一般為IT9－IT7級，表面粗糙度Ra一般為3.2－0.8μm。
- 6月 24 週一 201313:45
anticlockwise milling and clockwise milling
Milling is one of the most common and most widely used processing methods, and for roughing milling of the various structural components and fine milling is almost by end milling. There are two ways, clockwise and anticlockwise milling, according to the cutting direction. The movement of the cutting edge and work piece is in the opposite direction or same direction, divided into the two kinds of conventional milling and climb milling.
Anticlockwise Milling:
Milling direction and feed in the opposite direction (milling against the feed) is anticlockwise milling; chip caused from the bottom into upper, so we also call it as up milling; Since the traditional processing and milling mostly used this way, so we also called it as conventional milling.
- 6月 17 週一 201314:46
Cutting Reference Data for End Mills of Various Materials
Effective working solution depends on correct cutters, operation method, and technology.
Usual cutting conditions and major influence factors of CNC machines.
D=diameter(mm)
N=rpm of one min of end mills(min-1)
z= number of flute
f= Feed volume per flute
f(mm/刃)
- 3月 21 週四 201309:01
The cutter materials and their contrast
This list includes eight cutter materials and their contrast as below:
Mono Diamond)
CO PCD
Si PCD
PCBN
Si3N4
SiC
WC
Steel
- 3月 06 週三 201309:10
How to choose woodworking cutters?--part2
Selection of woodworking cutters
identify the main technical parameters of the cutter
Main parameters:outer diameter, machining thickness, and the center diameter.
Other technical parameters: number of teeth, the direction of rotation, rotation speed, feed rate, clamping way, and cutter material.
Choose the structure type of cutter
According the request and characteristics of cutting object, and consideration from both the technical and economic aspects, select the whole cutters or welding cutters, assembly cutters, and combination cutter.
The choice of the cutter rotation direction
Cutter rotation direction is determined in accordance with the direction of rotation of the processing machinery spindle and the tool axis and the feed of the work piece relative position of the whole cutter, or assembling cutter, the inclination of the cutting blade relative to cutter radius determines the rotation of the cutter direction.
Selection of cutting amount of end mills
Cutting amount of end mills are including cutting speed, feed speed of work material, and depth of milling. Cutting speed depends on the rpm and the radius of the end mills .. feed rate depends on the requirements of cutting surface .. the surface roughness of work material largely depends on the feed rate per tooth during cutting process, too much feed will cause too rough surface of work piece; too small feed will cause burnt phenomenon on the surface, so the feed rate must be appropriate.
Operation stability of end mills
The stability of the cutter operation is to ensure that the basis of the machining accuracy and surface quality .. including two aspects: one is cutter excited vibration in machining due to external forces; the other is that cutter happens deformation by external forces.
Safety of milling process
The safety of the milling cutter includes the limitation of rotation speed, the limitation of chip thickness, height restrictions of molding cutter contour and the thickness of assembly cutter, and stretched limit.
Cutting timber is characterized by high speed cutting, the rotation speed of the milling cutters mostly above 3000 rpm. High speed cutting for timber brings high productivity and smooth surface .., it also brings a series of security problems. Therefore, when the spindle speed up to 9000 rpm, besides the cutter which diameter smaller than 16mm, it should prohibit to use assembly cutters and do strict testing and inspection for welding cutter.
It is necessary to limit chip thickness for avoiding overload of cutters. For end mills, the clamping method, cutter height, and thickness of work piece are with close relationship. When you ensure the thickness of work piece, mill diameter, and center diameter, the height of cutter reflects its own strength, stiffness, and capacity of cutting resistance. The height must be limited to ensure the safety of cutter usage.
The design point of welding end mills is clamping problem. No matter the body is cylindrical or disc-type, the blade clamp form must be guaranteed to provide sufficient clamping force to resist rotation centrifugal force .
- 1月 30 週三 201310:37
Cutter wear and life
Cutter wear is the result caused by the physical and chemical affects during cutting by heat and friction. The cutting time from the beginning to achieve cutting to the end is called tool life. Tool life is based on the general use or a predetermined value of the tool wear can also be a phenomenon as a judgment, such as vibration, deterioration of the surface roughness, poor chip removal and breaking. When tool life is ended, we should re-grind, translocation or abandoned. Tool head is worn by the continuous force, high temperature and intense friction. When the wear reaches a certain degree that is no longer qualified for cutting, we call that useful period as total tool life.
- 11月 21 週三 201211:55
Cutting Reference Data for End Mills of Various Materials
Effective working solution depends on correct cutters, operation method, and technology.
Usual cutting conditions and major influence factors of CNC machines.
D=diameter(mm)
N=rpm of one min of end mills(min-1)
z= number of flute
f= Feed volume per flute
f(mm/刃)
- 11月 14 週三 201214:17
The cutter materials and their contrast
This list includes eight cutter materials and their contrast as below:
Mono Diamond)
CO PCD
Si PCD
PCBN
Si3N4
SiC
WC
Steel
- 11月 04 週日 201208:38
The cutting tool for hardening material above HRC50
There are higher requirements and more difficulties for many hardened molds. Hence general carbide cutters cannot reach such request of accuracy. Therefore, it should pay more attention to selection of cutting tools for hardened material.
Since hardening material which HRC is above 50, with higher hardness, the carbide cutter is difficult to meet the processing requirements, it will cause badly wear even break after CNC machining for about ten minutes. General carbide cutters cannot reach the request accuracy because the hardened mold is with higher requirement and difficulty.
Some points for choosing cutters for machining hardened materials as below:
- 8月 17 週五 201209:24
How to choose woodworking cutters?--part2
Selection of woodworking cutters
identify the main technical parameters of the cutter
Main parameters:outer diameter, machining thickness, and the center diameter.
Other technical parameters: number of teeth, the direction of rotation, rotation speed, feed rate, clamping way, and cutter material.
Choose the structure type of cutter
According the request and characteristics of cutting object, and consideration from both the technical and economic aspects, select the whole cutters or welding cutters, assembly cutters, and combination cutter.
The choice of the cutter rotation direction
Cutter rotation direction is determined in accordance with the direction of rotation of the processing machinery spindle and the tool axis and the feed of the work piece relative position of the whole cutter, or assembling cutter, the inclination of the cutting blade relative to cutter radius determines the rotation of the cutter direction.
Selection of cutting amount of end mills
Cutting amount of end mills are including cutting speed, feed speed of work material, and depth of milling. Cutting speed depends on the rpm and the radius of the end mills .. feed rate depends on the requirements of cutting surface .. the surface roughness of work material largely depends on the feed rate per tooth during cutting process, too much feed will cause too rough surface of work piece; too small feed will cause burnt phenomenon on the surface, so the feed rate must be appropriate.
Operation stability of end mills
The stability of the cutter operation is to ensure that the basis of the machining accuracy and surface quality .. including two aspects: one is cutter excited vibration in machining due to external forces; the other is that cutter happens deformation by external forces.
Safety of milling process
The safety of the milling cutter includes the limitation of rotation speed, the limitation of chip thickness, height restrictions of molding cutter contour and the thickness of assembly cutter, and stretched limit.
Cutting timber is characterized by high speed cutting, the rotation speed of the milling cutters mostly above 3000 rpm. High speed cutting for timber brings high productivity and smooth surface .., it also brings a series of security problems. Therefore, when the spindle speed up to 9000 rpm, besides the cutter which diameter smaller than 16mm, it should prohibit to use assembly cutters and do strict testing and inspection for welding cutter.
It is necessary to limit chip thickness for avoiding overload of cutters. For end mills, the clamping method, cutter height, and thickness of work piece are with close relationship. When you ensure the thickness of work piece, mill diameter, and center diameter, the height of cutter reflects its own strength, stiffness, and capacity of cutting resistance. The height must be limited to ensure the safety of cutter usage.
The design point of welding end mills is clamping problem. No matter the body is cylindrical or disc-type, the blade clamp form must be guaranteed to provide sufficient clamping force to resist rotation centrifugal force .
