Common problems and solutions for cutting tools in deep hole machining

In the deep hole processing process, the dimensional accuracy, surface quality and tool life of the workpiece are often encountered. How to reduce or even avoid these problems is an urgent problem we need to solve.

1. There is a problem: the aperture is increased, the error is large

(1) The cause of the outer diameter of the reamer is too large or the burr of the hinge cutting edge is burr; the cutting speed is too high; the feed rate is improper or the machining allowance is too large; the main yaw angle of the reamer is too large; the reamer is bent; The cutting edge adheres to the cutting edge; the sharpening of the cutting edge is sharp when the sharpening is performed; the cutting fluid is not suitable for selection; the surface of the taper shank is not wiped clean or the cone is bumped when the reamer is installed; After the tail offset is loaded into the spindle of the machine tool , the taper shank cone interferes; the spindle bends or the spindle bearing is too loose or damaged; the reamer floats inflexibly; when the shaft is different from the workpiece and the hand reaming, the force of the two hands is uneven, so that the reamer shakes left and right.

(2) Solution Depending on the specific circumstances, reduce the outer diameter of the reamer; reduce the cutting speed; adjust the feed amount or reduce the machining allowance; appropriately reduce the lead angle; refurbish the reamer that is straight or scrapped; Carefully trimmed to the qualified with the oil stone; control the swing within the allowable range; select the cutting fluid with better cooling performance; before installing the reamer, the reamer taper shank and the oil splash inside the taper hole of the machine tool must be cleaned, and the cone surface has a bump Repair with light stone; repair the stalk flat end; adjust or replace the spindle bearing; re-adjust the floating chuck and adjust the coaxiality; pay attention to correct operation.

2. There is a problem: the aperture is reduced

(1) The cause of the reamer outer diameter dimension design value is too small; the cutting speed is too low; the feed rate is too large; the reamer main deflection angle is too small; the cutting fluid selection is not suitable; the reamer wear portion is not worn off during sharpening The elastic recovery reduces the aperture; when the steel is reamed, the margin is too large or the reamer is not sharp, and the elastic recovery is easy, the aperture is reduced, the inner hole is not round, and the aperture is unqualified.

(2) Remedy Replace the outer diameter of the reamer; appropriately increase the cutting speed; appropriately reduce the feed rate; increase the lead angle appropriately; select the oily cutting fluid with good lubrication performance; interchange the reamer regularly, correct the sharpening reamer Cutting part; When designing the size of the reamer, the above factors should be considered, or the value should be taken according to the actual situation; for the experimental cutting, take the appropriate margin and sharpen the reamer.

3. There is a problem: the hinged inner hole is not round

(1) Cause The reamer is too long, the rigidity is insufficient, and the vibration occurs during reaming; the main yaw angle of the reamer is too small; the reaming cutting edge is narrow; the reaming margin is biased; the inner hole surface has notches and intersecting holes; the hole surface There are sand holes and air holes; the spindle bearing is loose, there is no guide sleeve, or the clearance between the reamer and the guide sleeve is too large, and the workpiece is deformed due to the tight clamping of the thin-walled workpiece.

(2) Remedy The reamer with insufficient rigidity can adopt the reamer with unequal pitch. The reamer should be rigidly connected to increase the lead angle. The qualified reamer is used to control the hole position tolerance of the pre-machining process. Use unequal pitch reamer, use longer, more precise guide sleeve; use qualified blank; when using equal pitch reamer to ream more precise hole, adjust the machine tool spindle clearance, the guide sleeve fit clearance should be required Higher or with a proper clamping method to reduce the clamping force.

4. There is a problem: the inner surface of the hole has a distinct facet

(1) The cause of the reaming allowance is too large; the back angle of the cutting part of the reamer is too large; the hinge cutting edge is too wide; the surface of the workpiece has pores, blisters, and the spindle pitch is too large.

(2) Solution to reduce the reaming allowance; reduce the back angle of the cutting part; trim the width of the cutting edge; select the qualified blank; adjust the machine tool spindle.

5. There is a problem: the surface roughness of the inner hole is high.

(1) The cutting speed is too high; the cutting fluid is not properly selected; the main yaw angle of the reamer is too large, and the hinge cutting edge is not on the same circumference; the reaming allowance is too large; the reaming margin is not uniform or too small, The partial surface is not hinged; the reamer cutting part is out of tolerance, the cutting edge is not sharp, the surface is rough; the hinge cutting edge is too wide; the chip removal is not smooth; the reamer is excessively worn; the reamer is bumped, the cutting edge There are burrs or chippings; the edge has built-up edge; due to the material relationship, it is not suitable for zero degree front angle or negative front angle reamer.

(2) Resolve measures to reduce the cutting speed; select the cutting fluid according to the processing material; appropriately reduce the main declination, correctly sharpen the cutting edge; properly reduce the reaming allowance; improve the position accuracy and quality of the reaming front hole Increase the reaming allowance; use qualified reamer; repair the width of the burr; reduce the number of teeth of the reamer according to the specific situation, increase the space of the chip flute or use the reamer with the angle of the blade to make the chip removal smooth; replace the reamer regularly, Grinding the grinding area during sharpening; the reamer should take protective measures during the sharpening, use and transportation process to avoid bumps; for the reamer that has been bruised, the reamer that will be hurt by the special oil stone will be used. Repair, or replace the reamer; trimmed with oil stone to pass, using a reamer with a rake angle of 5 ° ~ 10 °.

6. There is a problem: the life of the reamer is low

(1) The cause of the reamer material is not suitable; the reamer burns during sharpening; the cutting fluid is not properly selected, the cutting fluid does not flow smoothly, and the surface roughness of the cutting portion and the reaming cutting edge is too high.

(2) Solution According to the processing material, the reamer material can be selected, and the hard alloy reamer or coating reamer can be used; the cutting grinding amount is strictly controlled to avoid burns; the cutting fluid is often selected according to the processing materials; the chip cooling is often removed. The chips, with sufficient pressure of the cutting fluid, have been refined or ground to meet the requirements.

7. There is a problem: the position of the hinged hole is too poor.

(1) Cause The guide sleeve is worn; the bottom end of the guide sleeve is too far from the workpiece; the length of the guide sleeve is short, the precision is poor, and the spindle bearing is loose.

(2) Remedy Regularly change the guide sleeve; lengthen the guide sleeve to improve the matching precision between the guide sleeve and the reamer gap; repair the machine tool in time and adjust the bearing clearance of the spindle.

8. There is a problem: the reamer knife blade is chipped

(1) The cause of the reaming allowance is too large; the hardness of the workpiece material is too high; the cutting edge is too large, the cutting load is not uniform; the main yaw angle of the reamer is too small, so that the cutting width is increased; the deep hole or the blind hole is hinged When the chips are too much, they are not removed in time and the teeth have been sharpened during sharpening.

(2) Solution to modify the pre-processed aperture size; reduce the material hardness or use a negative rake angle reamer or carbide reamer; control the swing within the acceptable range; increase the lead angle; pay attention to timely removal of chips or Bladed angle reamer; pay attention to the quality of the sharpening.

9. There is a problem: the reamer handle is broken

(1) The cause of the reaming allowance is too large; when the reaming hole is used, the coarse and fine reaming allowance and the cutting amount are not suitable; the reamer has a small space for chipping and the chip is clogged.

(2) Solving measures Modify the aperture size of the pre-machining; modify the margin distribution, reasonably select the cutting amount; reduce the number of reamer teeth, increase the chip space or grind the tooth gap.

10. There is a problem: the center line of the hole after reaming is not straight

(1) Caused by the deviation of the hole before the reaming, especially when the hole diameter is small, the original bending degree cannot be corrected due to the poor rigidity of the reamer; the main yaw angle of the reamer is too large; the guiding is poor, so that the reamer is It is easy to deviate from the direction in the reaming; the inverted cone is too large in the cutting part; the reamer is displaced in the middle of the intermittent hole; when the hand reaming, the force is too large in one direction, forcing the reamer to deflect toward one end, destroying the reaming The verticality.

(2) Solution Measures to increase the hole for reaming or boring process; reduce the main yaw angle; adjust the appropriate reamer; exchange the reamer with the guiding part or the lengthening cutting part; pay attention to correct operation.