In the process of deep hole machining, problems such as the dimensional accuracy, surface quality and tool life of the workpiece often occur. How to reduce or even avoid these problems is an urgent problem to be solved at present. The following are 6 common problems and solutions for deep hole machining of tools, I hope to help everyone!
1, the aperture increases, the error is large
(1) Causes
The design value of the outer diameter of the reamer is too large or the reamer cutting edge has burrs;
Cutting speed is too high;
Improper feed rate or excessive machining allowance;
The main declination angle of the reamer is too large;
reamer bent;
Chip edge adhered to the reamer cutting edge;
When sharpening, the swing of the reaming cutting edge is out of tolerance;
Inappropriate selection of cutting fluid;
When installing the reamer, the oil on the surface of the taper shank is not wiped clean or the taper surface is bumped;
After the flat tail of the taper shank is offset into the machine tool spindle, the taper shank taper interferes;
The main shaft is bent or the main shaft bearing is too loose or damaged;
Reamer floating is not flexible;
When the axis is different from the workpiece and the force of both hands is uneven when reaming by hand, the reamer shakes from side to side.
(2) Solutions
Appropriately reduce the outer diameter of the reamer according to the specific situation;
reduce cutting speed;
Properly adjust the feed or reduce the machining allowance;
Appropriately reduce the main declination angle;
Straighten or scrap bent unusable reamers;
Carefully trimmed with whetstone to pass;
The control swing is within the allowable range;
Choose cutting fluid with better cooling performance;
Before installing the reamer, the reamer taper shank and the inside of the taper hole of the machine tool must be wiped clean, and the taper surface with bumps must be polished with whetstone;
Grinding reamer flat tail;
Adjust or replace the spindle bearing;
Readjust the floating chuck and adjust the coaxiality;
Pay attention to correct operation.
2. Aperture reduction
(1) Causes
The design value of the outer diameter of the reamer is too small;
Cutting speed is too low;
The feed rate is too large;
The main declination angle of the reamer is too small;
Inappropriate selection of cutting fluid;
When sharpening, the worn part of the reamer is not worn off, and the elastic recovery reduces the aperture;
When reaming steel parts, if the allowance is too large or the reamer is not sharp, it is easy to produce elastic recovery, which reduces the aperture and the inner hole is not round, and the aperture is unqualified.
(2) Solutions
Replace the outer diameter of the reamer;
Appropriately increase the cutting speed;
Appropriately reduce the feed;
Properly increase the main declination angle;
Choose oily cutting fluid with good lubricating performance;
Replace the reamer regularly, and sharpen the cutting part of the reamer correctly;
When designing the size of the reamer, the above factors should be considered, or the value should be selected according to the actual situation;
For experimental cutting, take an appropriate allowance and sharpen the reamer.
3. The reamed inner hole is not round
(1) Causes
The reamer is too long, the rigidity is insufficient, and vibration occurs during reaming;
The main declination angle of the reamer is too small;
The reaming cutting edge is narrow;
The reaming allowance is biased;
There are gaps and cross holes on the surface of the inner hole;
There are blisters and pores on the surface of the hole;
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 after being removed due to the thin-walled workpiece being clamped too tightly.
(2) Solutions
The reamer with insufficient rigidity can use the reamer with unequal pitch, and the installation of the reamer should adopt rigid connection to increase the main declination angle;
Select qualified reamer to control hole position tolerance in pre-machining process;
Adopt reamer with unequal pitch, adopt longer and more precise guide sleeve;
Select qualified blanks;
When using an equal-pitch reamer to ream more precise holes, the spindle clearance of the machine tool should be adjusted, and the matching clearance of the guide sleeve should be higher or an appropriate clamping method should be used to reduce the clamping force.
4. The inner surface of the hole has obvious facets
(1) Causes
The reaming allowance is too large;
The rear angle of the cutting part of the reamer is too large;
The reaming cutting edge is too wide;
The surface of the workpiece has pores, sand holes and the spindle swing is too large.
(2) Solutions
Reduce the reaming allowance;
Reduce the clearance angle of the cutting part;
Grinding edge width;
Select qualified blanks;
Adjust the machine tool spindle.
5. The service life of the reamer is low
(1) Causes
Inappropriate reamer material;
The reamer burns when sharpening;
The selection of cutting fluid is inappropriate, the cutting fluid fails to flow smoothly, and the surface roughness value of cutting and reaming is too high.
(2) Solutions
Select the reamer material according to the processing material, and can use a carbide reamer or a coated reamer;
Strictly control the amount of sharpening and cutting to avoid burns;
Always choose the cutting fluid correctly according to the processing material;
The chips in the chip flute are often removed, and the cutting fluid with sufficient pressure is used for fine grinding or grinding to meet the requirements.
6. The center line of the hole after reaming is not straight
(1) Causes
The drilling deflection before reaming, especially when the hole diameter is small, cannot correct the original curvature due to the poor rigidity of the reamer;
The main declination angle of the reamer is too large;
Poor guidance makes the reamer easy to deviate from the direction during reaming;
The reverse taper of the cutting part is too large;
The reamer is displaced at the gap in the middle of the interrupted hole;
When reaming by hand, too much force in one direction forces the reamer to deflect to one end and destroys the verticality of the reamed hole.
(2) Solutions
Increase the hole reaming or boring process to correct the hole;
Decrease the main declination angle;
Adjust the appropriate reamer;
Replace the reamer with a guide part or an extended cutting part;
