Plastic Back-rest Chair Mould

According to long years' cooperation with our customers in plastic chair moulds, we conclude some points which the customers concern more. If you have the same mould project, you can check also.

Can the mould company tell the mould run shots? 

Many companies will say they will have 1 million or 5 million guaranteed. But God now how many can they guarantee. The guarantee for a mould run 1 million shots without any flashed? If you accept to cut the flash by your worker's heavy labour, I think you can use this mould for 10 million shots. So you need to check the steel hardness, and in the mould, if there is any parting area were welded. Normally the steel hardness should be HRC33.

How mould company make the parting line finishing is good if there will be any sharp edges?

Sharp edge on the chair is dangerous, in order to avoid the sharp edge, we have to do many points during the mould manufacturing:

1. mould parting design is correct or not

2. mould cavity and core thickness are enough or not

3. how you make the CNC milling the cavity and core

4. one stage finishing or several stage finishing

The wall thickness is even or not.

Hand working on the parting line also be one of the reasons for wall thickness is not even. Of course, most of the reason is from the plastic chair 3D design and poor polishing on the cavities and cores. So when we start a plastic chair design, we have to consider the wall thickness. Sometimes, we need to make some area a little thicker to be sure that the chair is strong enough. But we have to consider it seriously when it is needed. Because the uneven thick will caused the injection not balanced and also will cause the cooling time not even, This will affect the injection speed slow down milling is too rough, you can never get a chair with thickness even.

How about the stackable?

When the chair plastic design is doing, we have to check its stackability. And you also need to consider the deform possibility of the chair moulding.

How making the chair mould with less weight but strong enough?

When starting to make the plastic chair design, we have to consider the weight and the strength. You can make the bottom area be strong enough to add more ribs. But how about the leg, most back and armrest area? For this reason, you need to calculate or analyze the force of each area...in order to make a light chair strong enough, you can choose a very low MFI PP material. But in this way, you need to make the mould very strong and also you need to be sure the injection filling are available because you are using a material with MFI 4 or Max. 6.

How to keep your chair mould finishing long-lasting?

In order to make your mould cavity and core will not be rust by the plastic material, you need to be sure that the steel is high chrome and also the hardness is bigger than HRC33, if you will use some recycled material for injection, you need your chair mould to be hard chrome plated. Otherwise, you need to make the polishing from time to time.