Tool selection and replacement method of tool die processing engraving equipment

First, the core points of tool selection

(1) Selecting cutting tools according to the characteristics of processing materials

Material Type Recommended Tool Type Tool Material Selection Basis

Metal (steel, aluminum, etc.) cemented carbide knives, ceramic knives, tungsten steel and YT cemented carbide have high hardness and strong wear resistance, which need to resist high temperature and wear during metal cutting.

Non-metallic (plastic, wood, rubber) high-speed steel knives, diamond coated knives HSS, and diamond coating have small cutting resistance to avoid material cracking or hot melting, and diamond coating can improve the surface smoothness of non-metallic materials.

Special forming knives for composite materials (fiberboard, PCB board), micro-milling cutters, ultra-fine grained cemented carbide and PCD should give consideration to cutting accuracy and fatigue resistance to prevent delamination or burr.

(2) Selecting cutter parameters according to the processing technology requirements.

Tool diameter:

Fine carving (such as characters and patterns): choose a 0.1~3mm small-diameter knife to ensure the clarity of details;

Large-area cutting or grooving: use a 6~12mm large-diameter knife to improve processing efficiency.

Blade angle:

Metal processing: the rake angle is 5 ~ 15, and the rake angle is 10 ~ 20 to reduce the cutting resistance;

Non-metal processing: the rake angle can be increased to 20 ~ 30, reducing the risk of material tearing.

Blade length and helix angle:

Deep groove machining: select a long-edged tool (blade length ≥ groove depth), and the spiral angle is 30 ~ 45 to improve the chip removal ability;

Shallow surface carving: short-edged cutter (blade length ≤5mm) with small helix angle (15 ~ 25) to reduce vibration.

(3) Matching the tool specifications according to the equipment performance.

Spindle speed: high-speed equipment (≥ 24,000 rpm) is suitable for small-diameter knives (≤3mm), and low-speed equipment (≤ 10,000 rpm) is suitable for large-diameter knives;

Feed speed: The higher the hardness of the cutter material, the faster the feed speed can be (for example, the feed speed of cemented carbide cutter is 500 ~ 2,000 mm/min, and that of high-speed steel cutter is 200 ~ 1,000 mm/min).

Second, the standard process of tool replacement and matters needing attention

(1) Preparation before replacement

Shutdown and power failure: ensure that the equipment stops running completely and disconnect the power supply to avoid electric shock or mechanical injury;

Cleaning the spindle and the tool holder: wipe the spindle taper hole and the tool holder surface with a dust-free cloth to remove oil stains and chips and prevent eccentricity after installation;

Check the tool condition: observe whether the blade is cracked, worn or coated, and replace it immediately if the following conditions are found:

Blade notch ≥0.5mm or continuous wear zone width ≥ 0.3 mm;

There are obvious burrs and vibration lines on the machined surface, and there is no improvement after adjusting the parameters;

Abnormal sound or vibration increases abnormally during cutting.

(2) Tool installation steps

Tool handle and tool assembly:

Straight handle cutter: put the handle into the chuck and tighten the nut (the torque should meet the requirements of the equipment manual, too tight may damage the chuck, and too loose may lead to the cutter flying off);

Tapered shank cutter: aim at the tapered hole of the spindle, gently push the shank until it fits completely, and lock it with a pull rod or wrench.

Concentricity calibration:

Use a dial indicator to touch the periphery of the cutter, and manually rotate the spindle. If the runout is greater than ＞0.02mm, it is necessary to reinstall the cutter or check the accuracy of the chuck.

The runout of small-diameter cutter (≤1mm) should be ≤0.01mm, otherwise it is easy to break the cutter or affect the machining accuracy.

(III) Commissioning and testing after replacement

No-load running test: start the spindle to run at low speed (500~1000rpm) for 1~2 minutes to observe whether there is abnormal vibration;

Trial cutting verification: carry out small-scale cutting on the waste, and check:

Roughness of machined surface (e.g. Ra of metal parts should be ≤1.6μm, and non-metal parts have no edge collapse);

Dimensional accuracy (the error should be controlled within ±0.05mm, and the precision parts should be 0.02 mm);

Parameter adjustment: optimize the rotation speed and feed according to the trial cutting results. For example, the rotation speed of the new tool can be appropriately increased by 10%~20% to improve the cutting efficiency.

Third, the advanced skills of tool use and maintenance

Tool life management:

Record the processing time of each tool (for example, the service life of cemented carbide tool is about 8~15 hours when processing steel), and replace it in advance after reaching 70% of the estimated service life to avoid sudden tool collapse;

Cutting fluid/lubricant use:

Metal processing: use oily cutting fluid for cooling and lubrication to prevent the tool from overheating;

Non-metallic processing: wood, plastic, etc. can be dry-cut, but easy-to-melt materials such as PVC need to be air-cooled or micro-sprayed;

Tool storage specification:

Store it with a special tool holder or packing box to avoid blade collision. Diamond tools should be stored separately to avoid scratching the coating.

Fourth, common problems and solutions

Possible causes of problems and solutions

Frequent cutter breakage, too high rotational speed/too high feed rate, reducing rotational speed by 10%~20% and reducing feed rate.

Tool with rough surface is worn/the blade angle is improper. Replace the tool and adjust the rake angle and rake angle.

After the tool is installed, the eccentric chuck is worn/the handle has impurities. Clean the chuck, replace the worn parts, and use the high-precision handle.

By scientifically selecting tools and standardizing the replacement process, the accuracy and efficiency of tool die processing can be significantly improved, and the service life of equipment and tools can be prolonged. In actual operation, it needs to be flexibly adjusted according to the material characteristics, equipment performance and processing requirements, and refer to the technical parameter table provided by the tool manufacturer when necessary.