by Leo Chang
Machining thin materials is not a tough job, as long as you have a good machine and the right techniques
You may wonder whether this thin material is real. It is. Here are the secrets to machining a thin workpiece like this.
1). Machining features
- It’s a NAK-80 tetragonal body machined in one setup.
- The diameter of the needle bottom is 0.5 mm, top is 0.005 mm and height is 30 mm.
- No damage after machining nine needles continuously.
- The thickness of thin plate is 0.3 mm, height is 30 mm.
- The width and depth ratio is 1:60; no tool marks after machining.
Machining a thin workpiece like this requires two conditions: a high precision and stable machining centre and excellent machining techniques.
2.) Overcoming problems during machining
There are problems you may encounter when attempting to machine thin workpieces. If positional accuracy on your machine is not precise, if the rigidity of your machine is not strong enough, if the spindle and tool are not good, they will generate tool marks, break the needles and lead to further machining problems. As well, high pressure coolant may slant the needle bar. If the needle bar is not rigid enough, it may cause the needle to break when machining. You cannot cut thin plate in one setup, and repetitive cutting may lead to tool marks and impact the quality of surface finish.
3.) Conditions for successful machining
- Success depends on having a high precision and stable machining centre. Your machine must not allow tool marks during machining. You must have a machine that achieves positional accuracy and repetitive positioning accuracy.
- You need a high precision spindle with a spindle balancing level of G0.4 (low vibration spindle) with spindle runout of 0.005/300 mm for better dynamic accuracy.
- You need the right tool designed with a sintered shank that will provide better precision of yaw and avoid breaking the needle bar. Lubrication is important. Use
- a MQL(Minimum Quantity Lubrication) system.
4.) Machining tips
- Small needle machining: First, recognize that needles may break due to the height of the needles (30 mm) and to cutting overload. Under this condition, use special cutting methods to overcome this problem.
- Thin plate machining: We designed a special tool for this machining, one that will not generate vibrations when cutting rest layers.
A high precision machining centre is key to success when machining thin materials, but you must employ advanced machining techniques and skill to ensure that success. SMT
Leo Chang is senior application engineer with Hartford.