◆Pore size increase

Causes of occurrence: the design value of the cutter diameter is too large or the cutter edge has burrs; the cutting speed is too high; the feed is improper or the machining allowance is too large; the main cutting edge of the cutter is too large; the cutter is bent; the cutter edge adheres to the built-up chip; the cutter edge is out of tolerance during grinding; the cutting fluid is not properly selected; the surface of the cutter shaft is not wiped clean of oil or the cone surface is knocked during installation of the cutter; the flat tail of the cutter shaft is out of position after being inserted into the main shaft of the machine tool, and the cone interferes; the main shaft is bent or the main shaft bearing is too loose or damaged; the cutter floats unflexible; the cutter is not coaxial with the workpiece and the two hands are not evenly force when hand-tapping, which makes the cutter sway left and right.

Remedies: Reduce the outer diameter of the die according to the specific situation; reduce the cutting speed; adjust the feed or reduce the machining allowance appropriately; reduce the main cutting edge angle appropriately; straighten or scrap the bent and useless die; carefully hone it to the standard with oil stone; control the swing within the allowable range; select the cutting fluid with better cooling performance; before installing the die, the inside of the die cone and the machine tool spindle cone hole must be wiped clean of oil, and the cone surface with bumps should be polished with oil stone; grind the flat tail of the die; adjust or replace the spindle bearings; readjust the floating chuck and adjust the coaxiality; pay attention to the correct operation.

◆Pore size reduction

Causes: the design value of the cutter diameter is too small; the cutting speed is too low; the feed rate is too large; the main cutting edge of the cutter is too small; the cutting fluid is not suitable; the worn part of the cutter is not ground during grinding, and the elastic recovery makes the hole diameter smaller; when cutting steel parts, if the allowance is too large or the cutter is not sharp, it is easy to produce elastic recovery, which makes the hole diameter smaller and the hole round, and the hole diameter is not qualified.

Remedies: replace the cutter with a larger outside diameter; increase the cutting speed appropriately; decrease the feed rate appropriately; increase the primary relief angle appropriately; select a cutting fluid with good lubricity; replace the cutter regularly and grind the cutting part of the cutter correctly; when designing the size of the cutter, the above factors should be considered or the values should be determined according to the actual situation; perform experimental cutting, take an appropriate allowance, and grind the cutter sharply.

◆The position accuracy of the counterbore hole is out of tolerance

Causes: wear of the guide bush; the distance from the bottom of the guide bush to the workpiece is too far; the guide bush is short in length and has poor accuracy, and the spindle bearings are loose.

Remedial measures: replace the guide bush regularly; extend the guide bush to improve the accuracy of the fit between the guide bush and the auger; repair the machine tool in time and adjust the clearance of the main shaft bearings.

◆ Counter沉 hole is not round

Causes of generation: the auger is too long, insufficient rigidity, and vibration occurs during drilling; the main cutting edge of the auger is too small; the auger cutting edge is narrow; the allowance for drilling is too small; there are notches, cross holes on the inner hole surface; there are sand holes, gas holes on the hole surface; the main shaft bearing is loose, there is no guide bush, or the clearance between the auger and the guide bush is too large, and the workpiece deforms after clamping due to the thin wall of the workpiece.

Remedial measures: For a hinge with insufficient rigidity, an uneven tooth pitch hinge can be used. The hinge should be installed with a rigid connection and the main clearance angle should be increased. Select a qualified hinge and control the position tolerance of the pre-machined hole. Use an uneven tooth pitch hinge and use a longer and more precise guide bush. Select a qualified blank. When using an equal tooth pitch hinge to machine a more precise hole, the clearance of the machine tool spindle should be adjusted. The clearance of the guide bush should be required to be higher or use an appropriate clamping method to reduce the clamping force.

◆The life of the milling cutter is low

Causes: inappropriate material for the die; the die was burned during grinding; inappropriate cutting fluid, the cutting fluid did not flow smoothly, and the surface roughness value of the machined cutting edge after grinding was too high.

Remedies: Select the material of the tap according to the material to be processed, hard alloy tap or coated tap can be used; strictly control the cutting amount during grinding to avoid burning; often select the cutting fluid correctly according to the material to be processed; often clear the chips in the chip removal groove, use sufficient pressure of cutting fluid, and grind or Grinding to the required accuracy.

◆High surface roughness value of inner hole

Causes of occurrence: excessive cutting speed; inappropriate cutting fluid selection; large main cutting edge angle of the Reamer, the cutting edges are not on the same circle; too large allowance for hole machining; uneven or too small allowance for hole machining, local surface not machined; cutting part of the Reamer is out of tolerance, cutting edges are not sharp, surface roughness; too wide cutting edge of the Reamer; poor chip removal during hole machining; excessive wear of the Reamer; damage to the Reamer , burrs or chipping of the cutting edges; built-up chips on the cutting edges; not suitable for zero degree positive cutting edge or negative cutting edge Reamer due to material reasons.

Remedies: reduce cutting speed; select cutting fluid according to the workpiece material; properly reduce the main cutting edge angle, and correctly grind the cutting edge of the Reamer; properly reduce the allowance of the hole to be counterbored; improve the position accuracy and quality of the bottom hole before counterboring or increase the allowance of the hole to be counterbored; select qualified counterbores; grind the width of the cutting band; reduce the number of teeth of the counterbore according to the specific situation, increase the space of the chip flute or use a counterbore with a negative cutting edge angle to facilitate chip removal; replace the counterbore regularly, and grind the grinding area away when grinding; the counterbore should be protected during grinding, use and transportation, and avoid bumps; for the counterbore that has been bumped, it should be repaired with a fine oil stone, or the counterbore should be replaced; use an oil stone to grind to qualified, using a counterbore with a front angle of 5 ° ~ 10 °.

◆The inner surface of the hole has a distinct the tuna

Causes: too large allowance for counterboring; too large rear angle of cutting part of the counterboring tool; too wide cutting belt of the tool; surface of the workpiece has blowholes, sand holes and the main shaft has too large play.

Remedial measures: reduce the allowance of the hinge hole; reduce the back angle of the cutting part; grind the width of the cutting edge; select qualified blank; adjust the main shaft of the machine tool.

◆Chisel tooth breakage

Causes: too large allowance for drilling; too high hardness of workpiece material; too large cutting edge deviation, uneven cutting load; too small main cutting edge angle of the reamer, which increases the cutting width; too much chips when drilling deep holes or blind holes, and failure to remove the chips in time and the teeth are already ground when grinding.

Correction measures modify the preprocessed hole diameter size; reduce the hardness of the material or change to a negative front angle hinge or a hard alloy hinge; control the swing difference within the qualified range; increase the main cutting edge; pay attention to the timely removal of chips or use a hinge with a negative edge; pay attention to the quality of grinding.

◆Chisel handle broken

Causes: too large allowance for reaming; improper distribution of allowance and cutting data selection for reaming conical holes; small chip space of reamer cutting teeth, chip blockage.

Remedial measures: modify the preprocessed hole diameter; modify the allowance distribution, and select the cutting parameters reasonably; reduce the number of cutting edges of the tap, increase the chip space, or grind off one tooth of the cutting edge.

◆The center line of the hole after drilling is not straight

Causes of generation: The deviation of drilling before reaming, especially when the hole diameter is small, the rigidity of the reamer is poor, and it cannot correct the original bending; the main cutting edge of the reamer is too large; poor guidance, which makes the reamer easily deviate from the direction during reaming; the cutting part is too ; the reamer moves back and forth at the middle clearance of the hole; when reaming by hand, too much force is applied in one direction, forcing the reamer to deviate to one end, destroying the perpendicularity of the reamed hole.

Remedies: correct the hole by increasing the boring or drilling process; reduce the main cutting angle; adjust the approp riate reamer; exchange the reamer with a guide part or a longer cutting part; pay attention to the correct operation.