What reduces the vibration in a milling machine

A. Assessment of wear and defects in turning

B. Assessment of drilling errors

1. Splitting the drill

Play of the drilling machine spindle in the axial direction. Resilient clamping of the workpiece. Too much advance. Remedy: Eliminate dead pass in spindle. Clamp the workpiece firmly. Reduce the feed rate.

2. Breakage of the drill

Bad fit in the lining. Inadequate removal of chips from the borehole. Drilled into the material over the outlet of the spiral. Worn or poorly sharpened drills. Remedy: Clamp the drill tightly. Frequent emptying of the grooves; take longer drills. Do not drift into the material via the outlet. Sand down in good time and in accordance with regulations.

3. Drill hooks and breaks

Porous areas in the material; inclined exit surface. Remedy: Reduce the feed rate. Clamp the workpiece well. Be careful when drilling by hand.

4. Chamfers rub off 

Too high speed, poor cooling. Remedy: Reduce speed, add sufficient lubricant.

5. The drill becomes blunt quickly

Feed too big, bad cooling. Remedy: Sharpen the drill bit, reduce the feed rate, add sufficient coolant.

6. Drill rears up, springs back the drill when it exits, drill breaks feed pressure too high, machine too weak. Remedy: Reduce the feed rate, do not load the machine higher than the design allows.

7. Breakage of thin drill bits

The drill protrudes too far from the chuck. Remedy: If possible, guide in drill bushes, otherwise clamp the drill halfway. Drill the hole at half depth, clamp the drill so that it protrudes. Drill the hole to the end.

8. Cylindrical drill shaft shows grooves

The drill bit was not clamped tight enough to allow it to slip. Drill overstressed due to too high a feed rate. Drill grooves clogged with chips, resulting in high friction. Remedy: Clamp the drill firmly and deep enough in the chuck. Reduce the feed rate. Often remove the chips from clogged chip flutes.

9. The ejector flap is broken or damaged

The clamping cone was greasy or dirty or had burrs, so that the cone lobes had to transmit the entire torque. Forcible loosening can also cause damage. Drilling of pre-drilled holes: the drill gets hooked and loses contact in the Morse taper. Remedy: Clean the clamping cone of grease and dirt before inserting it. Burr must be eliminated. Loosening should only be done by hand with the wedge driver. Main cutting edge correction, i.e. reducing the rake angle. Grind according to DIN 1412 B.

10. The drill tip shows tarnishing

The drilling machine has overheated due to excessive cutting speed or insufficient cooling. The feed rate was too great for deep holes. Remedy: Reduce the cutting speed by reducing the speed. Provide adequate cooling. Reduce the feed rate for deep holes.

11. The hole is larger than the nominal diameter of the drill

The drill is ground incorrectly so that the cutting edges are of different lengths. Remedy: Grind the drill correctly according to the apprenticeship or, better, on special machines.

12. The bore shows bulges and burrs

Drill was blunt. Burr formation at the exit point can also occur when drilling without a support and when the feed rate is too great while the drill passes through. Remedy: Use only sharply ground drills and suitable supports. The feed rate must be reduced when the drill passes through.

13. The bore wall is very rough

The drill was blunt, the feed rate too high or the lubrication insufficient. Remedy: sharpen the drill bit, reduce the feed rate, add a sufficient quantity of suitable lubricant.

14. The hole is crooked

Workpiece was clamped at an angle or was not positioned correctly because the documents were crooked or chips were under the workpiece, the documents or under the vice. Remedy: Place the workpiece in a vice on parallel pieces of the same height or use straight supports. Clean the drilling table from chips beforehand.

15. The hole is out of round, crooked and running

It was drilled with too much feed pressure; as a result, the drill bit bent or the machine reared up. Hole center and drill tip do not match. Bohrer struck. Remedy: Reduce the feed rate so that the feed force is reduced. Align the workpiece exactly according to the drill tip. Ensure that the drill runs smoothly.

16. The drill runs much more smoothly after pulling out the drill than when drilling

The drill hits or the workpiece has been inaccurately aligned with the drill tip when drilling. Remedy: Clamp the drill continuously and align the workpiece with the drill tip before drilling.