Views: 1 Author: Site Editor Publish Time: 2022-04-20 Origin: Site
1. Tool material
The common tool materials in tool grinding are: high speed steel (HSS), powder metallurgy high speed steel (PM-HSS), hard alloy (HM) and PCD, CBN, cermet and other super hard materials. High speed steel cutting tools are sharp and tough, while hard alloy cutting tools are hard but tough. The density of carbide tool is obviously higher than that of HSS tool. These two materials are the main materials of drill, reamer, milling cutter and tap. The performance of POWDER metallurgy high speed steel is between the above two materials and is mainly used to manufacture rough milling cutters and taps.
High speed steel tools are less sensitive to collision because of their good toughness. But carbide tool hardness is high and brittle, very sensitive to collision, easy to jump edge. Therefore, in the process of grinding, it is necessary to be very careful about the operation and placement of cemented carbide tools to prevent collisions between tools or tools falling.
Because the precision of high speed steel tool is relatively low, its repair and grinding requirements are not high, coupled with its price is not high, so many manufacturers set their tool workshop to repair and grinding. But the carbide tool often needs to be sent to the professional grinding center for grinding. According to the statistics of Arnold tool grinding center, more than 80% of the cutting tools are hard alloy tools.
2. Cutting tool grinding machine
Because of the hard of tool material, generally can only use grinding to change its shape. There are several common tool grinding machines in tool manufacturing and grinding:
1） Groove grinding machine: Groove or back for grinding drills, endmills, etc
2） Grinding tip Angle machine: Grind the cone Angle of the drill bit.
3） Cutting edge machine: Correct the edge of the drill bit.
4） Manual universal tool grinding machine: Grinding outer circle, groove, back, vertex Angle, horizontal edge, plane, front knife surface, etc. Often used for a small number of complex shape cutter.
5） CNC grinder: Generally five axis linkage, function determined by software. Generally used for grinding large number, high precision requirements, but not complex tools, such as drill, end milling cutter, reamer, etc.. The main suppliers of such grinding machines are from Germany, Switzerland, the United States, Australia and Japan.
3. Ggrinding wheel
1) The abrasive grain
The abrasive grains of different materials of grinding wheel are suitable for grinding tools of different materials. Different parts of the tool require different abrasive sizes to ensure the best combination of edge protection and machining efficiency.
2) The shape
In order to facilitate the grinding of different parts of the tool, the grinding wheel should have different shapes. The most commonly used are:
Parallel grinding wheel (1A1) : grinding apex Angle, outside diameter, back, etc.
Disc grinding wheel (12V9, 11V9) : Grinding spiral groove, milling cutter main and auxiliary cutting edge, trimming edge, etc.
After a period of use, the grinding wheel needs to modify its shape (including plane, Angle and rounded Angle R). In order to improve the grinding ability of grinding wheel, the chip filling between the grinding grains must be removed frequently with a cleaning stone.
4. Grinding standard
Whether to have a good tool grinding standards is to measure whether a grinding center is professional standards. Standard of grinding, the general rules for different cutting tool in cutting different materials when the cutting edge of technology parameters, including the blade Angle, apex Angle, rake Angle, Angle, blade, after chamfering etc parameters (in the carbide drill, make the blade passivation process is called "blade", pour the width of the blade and the cutting material, generally between 0.03 0.25 Mm. Chamfering at the edge (tip) is called chamfering. Every professional company has its own grinding standards summed up over the years.
5. Tool testing equipment
Tool testing equipment is generally divided into three categories: knife instrument, projector and universal tool measuring instrument. Tool instrument is mainly used for machining center and other CNC equipment tool preparation (such as length, etc.), but also used to detect Angle, radius, ladder length and other parameters; The function of the projector is also used to detect parameters such as Angle, radius and ladder length. But the above two generally cannot measure the tool Angle. The universal tool measuring instrument can measure most of the geometric parameters of the tool, including the back Angle.
Therefore, tool professional grinding center must be equipped with universal tool measuring instrument. But there are few suppliers of the equipment. German and French products are on the market.