Recently, I received a question from a netizen: I have been studying CNC lathes for a year and a half, and I have recently discovered a problem. Why do iron filings always wrap around the workpiece when I use a 35 ° machine to clamp and machine parts?

Processing part drawings

Q1: Coarse turning speed S1000 Iron filings wrapped around the workpiece

Q2: s800 unilateral 2mm F0.25 consequences

Suggestions from fellow knife enthusiasts

At the machining site, various situations may arise at any time. Some people say that “machining site is like a girl’s makeup”, pursuing the perfection of the results. However, which link in the middle has a problem and how should it be adjusted? Although I cannot see the processing site, I have compiled some information on how to deal with problems such as iron filings always getting tangled with the knife during processing.

How to deal with iron filings always getting tangled in the knife during processing?

1、 The rough outer circle of the car should be machined at an oblique angle at the starting point.

2、 At the beginning of the precision machining, it is most prone to chip entanglement. The speed should be reduced appropriately, and the feed rate does not need to be too slow. Start chamfering, retreat the tool by 3 millimeters, and let the chamfered iron chips be discharged. Increase the speed, and then turn the workpiece in a straight line at the required feed rate for the subsequent rod diameter.

3、 When rough turning, the current shaft diameter allowance should be adjusted evenly, without any taper (sometimes to reduce the vibration of the blade). Then gradually increase or decrease the margin by 0.2mm to solve the problem!

4、 The cutting fluid must be poured onto the cutting edge of the tool, taking into account the location of the entire shaft’s cutting edge. (As shown in the figure below)

5、 The main deviation angle should not be too small. If there is no actual need, try to be as large as possible. The main deviation angle is usually 75 ° when the non right angled step axis is used.
6、 Speed and feed rate.

1. When turning with a groove cutter, the faster the speed, the easier it is to get tangled, especially at the starting point. The speed should be reduced, and if necessary, the feed rate should be increased.

2. For debris knives, simply increase the feed rate. (Attention should be paid to ensuring roughness)

7、 When using a regular triangular groove cutter to cut grooves without strict regulations of 1mm or 2mm depth, adding the blank allowance increases the allowance. In addition, in this case, to ensure the symmetry of the groove wall on both sides and the angle of the groove wall, the main deviation angle is small, making it particularly prone to chip entanglement.

1. First, cut a blank section with the same diameter as the outer circles at both ends, and then run towards the outer circle of the blank at an oblique angle, which is smaller than the main angle of the current knife. Returning closer to the outer circle, start cutting the groove. The feed rate should not be too slow, and the speed should also be well coordinated. The speed must not be too fast (when the feed rate is 150%, the programmed “F” value is around 160 to 260, and the spindle speed is around 1500 to 1700 r/min, but it is not necessarily within this range. It should be determined according to the actual situation, product needs, machine performance, and lathe experience).

2. For safety reasons, reduce the probability of chip entanglement and ensure the reduction of edge burrs caused by excessive clearance of the workpiece. It is best to divide the turning into two stages. When rough turning, reduce the speed appropriately, increase the feed rate appropriately for turning, and reserve less margin for fine turning. When fine turning, increase the speed and feed rate to ensure roughness and timeliness.

8、 The material of the product needs to use cutting tools with appropriate hardness. Products with softer materials require sharp blades and smooth chip removal grooves, while products with harder materials require slightly dull blades. A chip knife can be chosen to avoid entanglement.

9、 When using a slotted knife, do not let the iron filings fall vertically from the tip of the knife. Instead, install an iron hook to allow the iron filings to hang down at a distance from the workpiece.

10、 When processing aluminum parts, do not use ordinary steel cutting blades to remove the aluminum, and do not add cutting fluid as it may oxidize. Aluminum blades generally have a front angle of 35 to 45 degrees, and the tip must be sharp. The speed should be high, with a line speed of around 800, which means that the machine tool should be driven as fast as possible. A larger feed F value is beneficial for chip breakage. Aluminum generally has a large front corner, so it is important to choose a suitable blade and be aware that aluminum is a non-ferrous metal. If you use steel blades, the quality must be poor and they are prone to stabbing.