Zamak 3 is the de facto standard for the zamak series of zinc alloys; all other zinc alloys are compared to this. Zamak 3 has the base composition for the zamak alloys (96% zinc, 4% aluminum). It has excellent castability and long-term dimensional stability.
Because of its strength, ductility and also excellent plating and finishing character, zamak 3 is popular indoor handles, door hinges, belt buckles, sliders etc. This article shows the process of how to finish the zamak 3 furniture hinges from casting.
1. Parts condition before finishing
Material: zamak3 die casting parts
Appearance: dull and grey. De-molding burr at the edge and around the hole
Shape: heavy parts with simple geometry. This part has multiple holes, so we need to take care to prevent undersized media login in.
Process before: die casting
Process after: electroplating
2. Parts surface requirement
- Smooth surface and low Ra value
- Remove loose burr generated from die casting
- Avoid parts hitting
- Avoid media lodge in
3. How we process the parts
|Step||(1) Deburring||(2) Drying|
|Machine||Vibratory finishing machine without separation||Vibratory dryer|
|Tumbling Speed||50/60HZ (full speed)||50/60HZ (full speed)|
|Chip Type||Plastic media 20×20 Cone Middle cutting||Corn Cob tumbling media|
|Media to Parts Ratio||6:1||6:1|
|Compound Type||LC-13 pH 8.5 (mild grinding compound)|
|Water Level||Just cover the mass|
|Tumble Time||1.5 hours||10 mins|
|Notes—||Manually take the parts out of the vibratory bowl||With PVC (or Nylon) separation sieve|
4. Parts condition before and after polishing
After the vibratory deburring process, the loose scales at the edge are removed. The entire surface is now matte finish texture.
You could also see from the side, the part have a de-molding line (parting line) that can not be removed with mass finishing process. This heavy burr has to remove by wheel grinding process manually before vibratory mass finishing.
5. Other considerations
This zamak 3 part is quite heavy, so media and parts ratio should higher to prevent parts from hitting each other.
The zamak 3 parts are very easy to corrosion. So parts need to dry as soon as the deburring process finish.
Some manufacturers introduce the dry tumbling process to deburr with a rubber-based plastic media. When you use this dry tumbling process, no water is involved. Again, their vibratory finishing machine equipped with an extra dust collection device.
This article introduces an example of zamak 3 parts deburring and smoothing. Firstly, we show the parts condition before tumbling. Then we talk about parts surface requirement, the process to improve the finish, comparison before and after finishing in turn. Finally, we also discuss the dry tumbling process is also an excellent way to finish the zamak 3 parts.