Ten common problems and solutions of the hottest r

2022-10-14
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Ten common problems and solutions in reaming machining

in the process of reaming, many problems such as out of tolerance of aperture and high surface roughness of inner hole often occur. The following summarizes the top ten problems and solutions of reaming processing

1. The hole diameter increases and the error is large

the design value of the outer diameter of the reamer is too large or the reamer edge has burrs; Cutting speed is too high; Improper feed or excessive machining allowance; The main deflection angle of reamer is too large; Reamer bending; The cutting edge of the reamer is adhered with a chip tumor; When grinding, the swing error of the reamer edge is out of tolerance; Improper selection of cutting fluid; When installing the reamer, the oil stain on the surface of the taper shank is not cleaned or the taper surface is bruised; After the flat tail of the taper handle is offset and installed into the spindle of the machine tool, the taper of the taper handle interferes with the taper; The main shaft is bent or the main shaft bearing is too loose or damaged; Reamer floating is not flexible; Different axis from the workpiece; When reaming by hand, the force of both hands is uneven, causing the reamer to shake left and right

solutions:

appropriately reduce the outer diameter of the reamer according to the specific situation; Reduce cutting speed; Adjust the feed rate appropriately or reduce the machining allowance; Properly reduce the main deflection angle; Straighten or discard the bent and unusable reamer; Carefully trim it with oilstone until it is qualified; Control the swing error within the allowable range; Choose cutting fluid with good cooling performance; Before installing the reamer, the oil stains inside the taper shank of the reamer and the taper hole of the machine tool spindle must be wiped off, and the bumps on the conical surface must be polished with an oilstone; Grinding the flat tail of reamer; Adjust or replace the main shaft bearing; Readjust the floating chuck and adjust the coaxiality; Pay attention to correct operation

2. The design value of the outer diameter of the reamer is too small; The cutting speed is too low; The feed rate is too large; The main deflection angle of reamer is too small; Improper 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, the allowance is too large or the reamer is not sharp, which is easy to produce elastic recovery and reduce the aperture; The inner hole is not round, and the hole diameter is unqualified

solutions:

replace the outer diameter of the reamer; Properly increase the cutting speed; Reduce the feed rate appropriately; Properly increase the main deflection angle; Choose oil-based cutting fluid with good lubricating performance; Exchange reamers regularly 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; Make experimental cutting, take appropriate allowance, and sharpen the reamer

3. The reamed inner hole is out of round

the reamer is too long, the rigidity is insufficient, and vibration occurs during reaming; The main deflection angle of reamer is too small; Reamer blade band is narrow; Reaming allowance deviation; There are notches and cross holes on the inner hole surface; There are sand holes and pores on the hole surface; The main shaft bearing is loose, there is no guide sleeve, or the fit clearance between the reamer and the guide sleeve is too large; Because the thin-walled workpiece is clamped too tightly, the workpiece is deformed after removal

solutions:

reamers with insufficient rigidity can adopt reamers with unequal tooth pitch, and the installation of reamers should adopt rigid connection to increase the main deflection angle; Select qualified reamers and control the hole position tolerance of the pre machining process; Reamers with unequal tooth pitch and longer and more precise guide sleeves are used; Select qualified blank; When using equal pitch reamers to ream more precise holes, the spindle clearance of the machine tool should be adjusted, and the fitting clearance of the guide sleeve should be higher; Adopt proper clamping method to reduce clamping force

4. There are obvious edges on the inner surface of the hole

the reaming allowance is too large; The back angle of the reamer cutting part is too large; Reamer blade band is too wide; There are pores and sand holes on the workpiece surface, and the levelness is 0.2/1000; The spindle runout is too large

solutions:

important leaders such as Chen Biao, vice mayor of Shenzhen Municipal People's government, and Mr. Xie Bingwen, deputy head of Nanshan District People's Government of Shenzhen, were invited to the bell ringing ceremony to reduce the reaming allowance; Reduce the back angle of the cutting part; Width of grinding blade belt; Select qualified blank; Adjust the spindle of the machine tool

5. The inner hole surface roughness value is high

the cutting speed is too high; Improper selection of cutting fluid; The main deflection angle of the reamer is too large, and the cutting edge of the reamer is not on the same circumference; Reaming allowance is too large; The reaming allowance is uneven or too small, and the local surface is not reamed; The swing of the reamer cutting part is out of tolerance, the cutting edge is not sharp, and the surface is rough; Reamer blade band is too wide; Poor chip removal during reaming; Excessive wear of reamer; The reamer is bruised, and the edge is burred or broken; There is debris accumulation on the cutting edge; Due to the material relationship, it is not applicable. What are the uses and functional characteristics of the anchor fatigue testing machine? 1. Let's look at the zero or negative rake reamer described below

solutions:

reduce the cutting speed; Select cutting fluid according to processing materials; Properly reduce the main deflection angle, and correctly grind the hinge to account for 17.60% of the cutting edge; Properly reduce the reaming allowance; Improve the accuracy and quality of the bottom hole position before reaming or increase the reaming allowance; Select qualified reamers; Width of grinding blade belt; According to the specific situation, reduce the number of reamer teeth, increase the space of chip holding groove, or use the reamer with blade inclination angle with CNC public number cncdar to make the chip removal smooth; The reamer shall be replaced regularly, and the grinding area shall be removed during grinding; During the grinding, use and transportation of reamers, protective measures should be taken to avoid bumping; For the bruised reamer, use extra fine oilstone to repair the bruised reamer, or replace the reamer; Use an oilstone to trim it to the qualified level, and use a reamer with a front angle of 5 ° - 10 °

6. The service life of reamer is low

the reamer material is inappropriate; The reamer is burned during grinding; The selection of cutting fluid is inappropriate, and the cutting fluid fails to flow smoothly at the cutting place; The surface roughness value of reamer after grinding is too high

solutions:

choose the reamer material according to the processing material, which can be cemented carbide reamer or coated reamer; Strictly control the cutting amount of grinding to avoid burns; Select the cutting fluid correctly according to the processing materials; Often remove the chips in the chip groove, and use cutting fluid with sufficient pressure to meet the requirements after fine grinding or grinding

7. The accuracy of the reamed hole position is out of tolerance

the guide sleeve is worn; The bottom end of the guide sleeve is too far from the workpiece; The guide sleeve is short in length and poor in accuracy; The spindle bearing is loose

solutions:

replace the guide sleeve regularly; Lengthen the guide sleeve to improve the fitting accuracy of the clearance between the guide sleeve and the reamer; Timely repair the machine tool and adjust the clearance of the spindle bearing

8. The reamer tooth chipping edge

reaming allowance is too large; The hardness of workpiece material is too high; The swing of cutting edge is too large, and the cutting load is uneven; The main deflection angle of reamer is too small, which increases the cutting width; When reaming deep holes or blind holes, there are too many chips and they are not removed in time; The cutter teeth have been worn apart during grinding

solutions:

modify the pre processed aperture size; Reduce the hardness of the material or use a negative rake reamer or carbide reamer; Control the swing error within the acceptable range; Increase the main deflection angle; Pay attention to remove the chips in time or use the reamer with blade inclination; Pay attention to the grinding quality

9. The reamer shank is broken

the reaming allowance is too large; When reaming taper holes, the allocation of rough and fine reaming allowance and the selection of cutting parameters are inappropriate; Reamer teeth have small chip holding space and chip blockage

solutions:

modify the pre processed aperture size; Modify the allowance allocation and reasonably select the cutting amount; Reduce the number of reamer teeth, increase the chip holding space or grind off one tooth of the cutter tooth clearance

10. The center line of the hole after reaming is not straight

the drilling hole before reaming is skewed, especially when the hole diameter is small, because the reamer has poor rigidity, it cannot correct the original curvature; The main deflection angle of reamer is too large; Poor guidance makes the reamer easy to deviate from the direction in reaming; The inverted cone of the cutting part is too large; The reamer moves at the gap in the middle of the intermittent hole; When hand reaming, excessive force in one direction forces the reamer to deflect towards one end, which destroys the perpendicularity of reaming

solutions:

increase the correction hole of reaming or boring process; Reduce the main deflection angle; Adjust the appropriate reamer; Exchange reamers with guide parts or extended cutting parts; Pay attention to correct operation

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