In this article, we will discuss aluminum case cover casting parts smoothing. These case cover parts are made from Aluminum alloy and it has machining mark which has to be removed. Aluminum is a lightweight material with specific gravity 2.72. Its rigid structure made it popular in construction and decorations.
1. Parts condition before finishing
Material: Aluminum alloy
Appearance: before processing, the majority of the surface of the parts is dull and grey. We can also observe the center parts have a machining mark. This mark needs to grind off. If we did not clear out this mark, it will show up after coating.
Shape: The aluminum case cover has a very simple geometry. However, the part has a small hole so we need to sieve out the small size media after some time.
Process before finishing: Die casting and Machining
Process after finishing: anodizing
2. Parts Surface requirement
- Smoothing parts surface without damage parts
- Remove the machining mark on the surface
- Remove the black layer generate from the die casting process
- Reduce surface roughness prepare for anodizing
3. How we process the parts
|Step||(1) Grinding||(2) Drying|
|Machine||Vibratory Finishing Machine (without separation)||Vibratory dryer/ Conveyor belt dryer|
|Tumbling Speed||50/60HZ (full speed)|
|Chip Type||Plastic Media TET/Cone Light cutting|
|Media to Parts Ratio||4: 1|
|Compound Type||LC-13, PH 8 (mild grinding compound)|
|Water Level||Just cover the mass|
|Tumble Time||1 Hour||5-10 min|
|Notes—||Manually take the parts out of the machine and rinse them|
4. Parts condition before and after polishing
Before vibratory finishing, aluminum parts are dirt and dark.
After processing, you can see the grayish oxidation layer is disappeared. Also, the machining mark in the main body is removed. The finished parts are ready for anodizing, and only take a fraction of time compared with manual finishing.
When we have a close look of the parts, we find aluminum parts surface forms matte finishing texture with a slight shine.
Because aluminum is a soft metal, and also we did not find large burr and defect. So we use plastic tumbling media with low cutting power.
5. Other considerations
Unlike zinc and Zamak3 material, aluminum is not easy to rust and corrosion. So we have more choices to get it dry.
This part has very small holes which diameter about 4mm. For small burr removal, choosing a media to enter every feature on the part is sometimes difficult. However, a tetrahedron can enter the groove and slots easier than a cone.
We can also use a rotary barrel tumbling machine. However, barrel tumbling takes a longer time. Anyway, after barrel tumbling parts have a better surface condition.
In this article, we give an example of aluminum case cover parts mass finishing with plastic deburring media. The same process may also be used for aluminum machining parts deburring and edge breaking.
Firstly, we discuss the parts condition before finishing. Secondly, we show parts surface requirement from clients. Thirdly, we show the process that we did for the aluminum parts in details. Later, we compare the surface before and after mass finishing. At last, we discuss other possibilities for aluminum parts smoothing.