To order high-quality chair mould, we have to be very careful to choose the mould company. If you want to know their quality of chairs mould, ask a few questions:
Chair mould quality points:
• Chair mould cycle
• Chair mould life
• Is parting line good? Are there sharp edges?
• Is the chair wall thickness uniform?
• How do they produce chairs mould to make the chair lighter weight and strong strength?
• How the chair superimposed like?
• How to design exhaust on backrest?
• How to make your chair polishing persistent?
Analysis for plastic injection chair moulds
1. How to determine the mould cycle?
If the cooling water temperature was 8-12 ℃, the weight of the chair at 1700g to 2400g, then the cycle should be 35s-50s. If the machine plastic injection molding and melt under the action of the accumulator, check their water design, whether the water channel is straight through? Is waterway trend consistent with the shape of the chair?
2. How to guarantee chair mould life?
Many people will say that they can guarantee one million shots. But who knows how they ensure this. They can also ensure that no burrs after mould run 1 million times? If you cut burrs manually, then I think you can produce 10 million of chairs. So you need to check the hardness of the steel material and check the chair mould whether has welded portion. Under normal circumstances, the hardness of the steel material should be HRC33.
3. How can you ensure that there is no sharp burr on the parting line?
It is dangerous if parting line is very rough on the chair, in order to avoid sharp edges, we must pay attention to many aspects of the production process in the mould:
— Is the chair mold parting line design correct?
– -Is cavity and core thickness enough?
– -How do you process the core and cavity? One time processing or multiple processing?
Normally we need three times processing. From roughing to harden steel material, after hardening steel material, and then a second phase of our CNC milling, we call this stage of semi-finished, normally we would leave 0.3mm tolerance and wait steel stress relief, then do the third fine finishing. This time the machine operation is very important.
1) It must be cooled in CNC milling area.
2) We need to ensure that each cutting process, the depth not more than 0.08mm. All this is in order to prevent material will be deformed after CNC milling and steel material hardened. Steel deformation will cause the core and cavity assembly is not accurate, and then will cause a lot of manual work. To carry out manual work on the parting area, you absolutely can not make a perfect parting line.
4. Is chair wall thickness uniform?
Manual work at the parting line is one of the reasons leads to uneven thickness. Of course, most of reasons are the plastic chair 3D design and poor polishing for the core and cavity. So when we begin to make a plastic chair mold design, we have to consider the thickness factor. Sometimes, we need to do is a little thicker in some areas in order to ensure the strength of the chair. But at the same time we have to think carefully about this issue. Because the uneven thickness will make injection result unevenness, and bring uneven cooling. This slows down the injection speed, and it will result in miniature. If the CNC milling process inaccurate, you absolutely can not get a uniform thickness chair.
5. Superimposed issue
When starting the chair design, we have to check its synergistic effect. At the same time you have to consider the possibility of deformation chair mould.
6. How do you ensure that the plastic chair light and have enough strength?
When designing chair product, we have to consider its weight and strength. You can add more ribs so that the bottom of the chair is strong enough. But what about the chair legs, back and seat cushion areas? On this, you need to analyze the intensity of each area. In order to make a lighter chair with good strength, you need to select the low melt index PP material. Provided that the chair mould must be very strong, filling the injection must be feasible because you are using a melt index of 4 or a maximum of 6 plastic materials.
7. How to design a good exhaust in the chair back?
Some of the backrest of the chair design is very complicated, because there are many plastic welding places. The venting may be bad when the material filling and flowing. So you have to use mould flow to analyze whether some areas require venting.
8. How to ensure the durability of the chair mould polishing?
In order to make the chair mould core and cavity not corrosive by plastic, you have to make sure the mould material is chrome-plated steel, the hardness more than 33. If you use some recycled materials for production, the chair mould must be chrome-plated. Otherwise, the mould should always need polishing.