In the process of deep hole drilling, there are often problems such as the dimensional accuracy, surface quality and tool life of the workpiece. How to reduce or even avoid these problems is a problem we need to solve at present. The following summarizes the common problems in deep hole processing. 10 kinds of problems and solutions.
1. Increased aperture, large error
(1) Reason
The design value of the reamer outer diameter is too large or the reamer cutting edge has burrs; the cutting speed is too high; the feed is improper or the machining allowance is too large; the reamer main deflection angle is too large; the reamer is bent; the reamer cutting edge is sticky Chip knobs are attached; the reaming of the cutting edge of the hinge is too poor during sharpening; the choice of cutting fluid is not suitable; the oil on the surface of the taper shank is not wiped clean or the taper surface is injured when the reamer is installed; The taper shank conical interference of the main shaft of the machine tool; the main shaft is bent or the main shaft bearing is too loose or damaged; the reamer is not flexible;
(2) Solution
Reduce the outer diameter of the reamer appropriately according to the specific situation; reduce the cutting speed; properly adjust the feed amount or reduce the machining allowance; appropriately reduce the main deflection angle; straighten or scrap the bent unusable reamer; carefully trim it with oilstone to Pass; control the swing within the allowable range; choose cutting fluid with better cooling performance; clean the oil inside the taper shank of the reamer and the taper hole of the machine tool spindle before installing the reamer; Grind the flat end of the reamer; adjust or replace the spindle bearing; readjust the floating chuck and adjust the coaxiality; pay attention to correct operation.
2. Reduction of aperture
(1) Reason
The design value of the outer diameter of the reamer is too small; the cutting speed is too low; the feed amount is too large; the main deflection angle of the reamer is too small; the cutting fluid is not selected properly; the worn part of the reamer is not worn out during sharpening, and the elastic recovery makes the hole diameter Shrinking; when reaming steel parts, the margin is too large or the reamer is not sharp, and elastic recovery is easy to occur, which reduces the hole diameter and the inner hole is not round, and the hole diameter is unqualified.
(2) Solution
Replace the outer diameter of the reamer; appropriately increase the cutting speed; appropriately reduce the feed amount; appropriately increase the main deflection angle; choose oily cutting fluid with good lubrication performance; regularly exchange the reamer and correctly sharpen the reamer cutting part; design the reamer When dimensioning the knife, the above factors should be taken into consideration, or the value should be taken according to the actual situation; for experimental cutting, take a suitable margin and sharpen the reamer.
3. The inner hole of the hinge is not round
(1) Reason
The reamer is too long and the rigidity is insufficient, and vibration occurs during reaming; the main deflection angle of the reamer is too small; the reamer cutting edge is narrow; the reaming margin is too small; the surface of the inner hole has a gap and a cross hole; the surface of the hole has trachoma and air holes; The main shaft bearing is loose, there is no guide sleeve, or the gap between the reamer and the guide sleeve is too large, and the thin-walled workpiece is clamped too tightly, and the workpiece is deformed after removal.
(2) Solution
Reamers with insufficient rigidity can use unequal pitches. The reamer should be installed with rigid couplings to increase the main deflection angle. Use qualified reamers to control the hole position tolerances of the pre-processing process. Use unequal pitches Reamers use longer and more precise guide bushings; qualified blanks are used; when reaming more precise holes with equal pitch reamers, the clearance of the machine tool spindle should be adjusted. The clearances of the guide bushings should be higher or appropriate. The clamping method reduces the clamping force.
4. The inner surface of the hole has obvious edges
(1) Reason
The reaming margin is too large; the back angle of the reamer cutting part is too large; the reaming cutting edge band is too wide; the surface of the workpiece has air holes, trachoma, and the main shaft swing is too large.
(2) Solution
Reduce the reaming margin; reduce the back angle of the cutting part; sharpen the width of the cutting edge; choose a qualified blank; adjust the machine tool spindle.
5. High surface roughness of inner hole
(1) Reason
The cutting speed is too high; the cutting fluid is not suitable; the reaming angle is too large, the reaming cutting edges are not on the same circle; the reaming margin is too large; the reaming margin is uneven or too small, and the local surface is not reamed to ; The reamer cutting part has excessive deviation, the cutting edge is not sharp, and the surface is rough; the reamer cutting edge is too wide; the chip removal is not smooth when the reamer is worn; the reamer is excessively worn; the reamer is injured, and the burr is left with burrs or chipping There is a built-up edge on the cutting edge; due to the material relationship, it is not suitable for zero rake angle or negative rake angle reamer.
(2) Solution
Reduce cutting speed; choose cutting fluid according to the processing material; appropriately reduce the main deflection angle and sharpen the reaming cutting edge properly; appropriately reduce the reaming margin; improve the position accuracy and quality of the front bottom hole or increase the reaming margin Select a qualified reamer; sharpen the blade width; reduce the number of teeth of the reamer, increase the chip flute space or use a reamer with a blade inclination angle to make chip removal smooth; replace the reamer regularly, and sharpen it when sharpening Grinding area is cut off; during resharpening, use and transportation, protective measures should be taken to avoid bumps; for bumps that have been damaged, repair the bumped reamer with extra fine oil stone or replace the reamer Knife; trimmed with oil stone to pass, using a reamer with a rake angle of 5 ° -10 °.
6. Low ream life
(1) Reason
The material of the reamer is not suitable; the reamer burns during the sharpening; the cutting fluid is not selected properly, the cutting fluid does not flow smoothly, and the surface roughness of the cutting place and the reamer is too high after grinding.
(2) Solution
Select the reamer material according to the processing material. Carbide reamer or coated reamer can be used. Strictly control the amount of sharpening and cutting to avoid burns. Always select the correct cutting fluid according to the processing material. Always clear the chips in the chip groove. The cutting fluid under pressure is finely ground or ground to meet the requirements.
7. Poor position accuracy of hinged holes
(1) Reason
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 accuracy is poor, and the spindle bearing is loose.
(2) Solution
Replace the guide sleeve regularly; lengthen the guide sleeve to improve the precision of the clearance between the guide sleeve and the reamer; repair the machine tool and adjust the spindle bearing clearance in time.
8. Reamer Tooth Bursting
(1) Reason
The reaming allowance is too large; the hardness of the workpiece material is too high; the cutting edge swing is too large, and the cutting load is uneven; the main deflection angle of the reamer is too small, which increases the cutting width; when reaming deep or blind holes, there are too many chips However, the teeth have not been removed in time and sharpened during sharpening.
(2) Solution
Modify the pre-machined hole size; reduce the hardness of the material or use a negative rake reamer or hard alloy reamer; control the swing within the acceptable range; increase the main declination angle; pay attention to clear chips in time or use a tilted reamer with a blade ; Pay attention to the sharpening quality.
9. The reamer shank is broken
(1) Reason
The reaming allowance is too large; when reaming a taper hole, the rough and fine reaming allowance allocation and cutting amount selection are not suitable; the reamer cutter tooth space is small and the chip is blocked.
(2) Solution
Modify the diameter of the pre-machined hole; modify the allocation of allowances and choose a reasonable amount of cutting; reduce the number of reamer teeth, increase the chip space, or remove one tooth clearance.
10. The centerline of the rear hole is not straight
(1) Reason
The drilling in front of the reaming hole is skewed, especially when the hole diameter is small, due to the poor rigidity of the reamer, the original curvature cannot be corrected; the main deflection angle of the reamer is too large; poor guidance makes the reamer easily deviate during reaming The cutting part has too large inverted cone; the reamer is displaced at the gap in the middle of the intermittent hole; when the hand is reamed, excessive force is applied in one direction, forcing the reamer to deflect to one end and destroying the verticality of the reamer.
(2) Solution
Increase the reaming or boring process to correct the hole; reduce the main deflection angle; adjust the appropriate reamer; replace the reamer with the guide part or the extended cutting part; pay attention to the correct operation.