A collection of common problems and solutions in tool deep hole machining

In the process of deep hole machining, problems such as dimension accuracy, surface quality and tool life often appear. How to reduce or even avoid these problems is an urgent problem to be solved.

1. The aperture increases and the error is large ‍‍‍‍

The reasons causing

The design value of reamer outer diameter is too large or the cutting edge of reamer is burr; Cutting speed is too high; Improper feed or processing allowance is too large; The main Angle of reamer is too large; Reamer bending; The chip tumor is adhered to the cutting edge of hinge cutting; When grinding, the edge swing of hinge cutting is out of tolerance; Cutting fluid selection is not appropriate; When the reamer is installed, the surface of the cone handle is not clean or the cone is bruised; The flat tail of the taper shank is tilted into the machine tool spindle after the taper shank conical interference; Spindle bending or spindle bearing is too loose or damaged; The reamer float is not flexible; With the workpiece is not coaxial and hand reaming when the force is not uniform, so that the reamer around shaking.

The solution

Reduce the reamer diameter appropriately according to the specific situation; Reduce cutting speed; Appropriate adjustment of feed or reduce processing allowance; Reduce the main deflection Angle appropriately; Straighten or scrap bent unusable reamers; Carefully trim with oilstone to qualified; Control the pendulum difference within the allowable range; Select cutting fluid with better cooling performance; Before installing the reamer, the reamer taper handle and the machine tool spindle taper hole must be cleaned, and the taper surface has a knock on the oil stone repair; Grinding reamer flat tail; Adjust or replace the spindle bearing; Re-adjust the floating clip and adjust the coaxiality; Pay attention to correct operation.

2. Aperture reduction

The reasons causing

The design value of reamer outer diameter is too small; Cutting speed is too low; Too much feed; The main Angle of reamer is too small; Cutting fluid selection is not appropriate; When grinding the reamer wear part is not worn off, elastic recovery to reduce the aperture; When reaming steel parts, the allowance is too large or the reamer is not sharp, it is easy to produce elastic recovery, reduce the aperture and the inner hole is not round, and the aperture is not qualified.

The solution

Replace the reamer outer diameter size; Appropriately improve the cutting speed; Appropriately reduce the feed; Appropriately increase the main declivity Angle; Select oily cutting fluid with good lubrication performance; Regularly exchange reamer and grind the cutting part of reamer correctly; When designing the reamer size, the above factors should be considered, or the value should be taken according to the actual situation; For experimental cutting, sharpen the reamer with a suitable margin.

3. The inner hole reamed is not round

The reasons causing

The reamer is too long, the rigidity is insufficient, and the vibration occurs when the reamer is hinged; The main Angle of reamer is too small; Narrow cutting edge belt; Reaming allowance deviation; The surface of the inner hole is notched and crossed; Hole surface with trachoma, pores; Spindle bearing loose, no guide sleeve, or reamer and guide sleeve fit clearance is too large and due to the thin-wall workpiece clamping too tight, after unloading workpiece deformation.

The solution

The reamer with unequal tooth distance can be used for the reamer with insufficient rigidity. The reamer should be installed with rigid connection to increase the main deflection Angle. Select qualified reamer to control the tolerance of hole position in pre-machining process; Using unequal pitch reamer, using longer, more precise guide sleeve; Selection of qualified blank; When the precision hole is hinged by the equal pitch reamer, the clearance of the spindle of the machine tool should be adjusted, and the clearance of the guide sleeve should be higher or the proper clamping method should be adopted to reduce the clamping force.

4. The inner surface of the hole has obvious edge surface

The reasons causing

Reaming allowance is too large; Too large rear Angle of reamer cutting part; Hinged cutting edge belt is too wide; The surface of the workpiece has holes, sand holes and the spindle swing is too large.

The solution

Reduce reaming allowance; Reduce the cutting part of the back Angle; Width of grinding edge belt; Selection of qualified blanks; Adjust the spindle of machine tool.

5. The inner hole surface roughness value is high

The reasons causing

Cutting speed is too high; Cutting fluid selection is not appropriate; The main deflection Angle of reamer is too large, and the cutting edge of reamer is not on the same circumference; Reaming allowance is too large; The reaming allowance is not uniform or too small, and the local surface is not reamed; Reamer cutting part of the pendulum out of tolerance, cutting edge is not sharp, rough surface; Hinged cutting edge belt is too wide; When reaming, chip removal is not smooth; Excessive reamer wear; The reamer is bruised, with burr or broken edge; The edge has a chip tumor; Not suitable for zero or negative rake reamer due to material.

The solution

Reduce cutting speed; Select cutting fluid according to processing materials; Properly reduce the main deflection Angle, correct cutting edge grinding hinge; Appropriately reduce reaming allowance; Improve the position accuracy and quality of bottom hole before reaming or increase the reaming allowance; Selection of qualified reamer; Width of grinding edge belt; According to the specific situation to reduce the number of reamer teeth, increase the chip slot space or the use of reamer with edge Angle, so that the chip discharge smoothly; Replace the reamer regularly, grind the grinding zone when grinding; In the process of grinding, use and transportation of reamer, protective measures should be taken to avoid bruise; For the reamer that has been touched, the reamer that has been touched should be repaired or replaced with a super fine whetstone; Trim to qualified with a whetstone, using a reamer with a front Angle of 5° ~ 10°.