 Sino Mould is the leading chair mould manufacturer in china. Annually manufacturing over than 80 sets of chair moulds.  Interchangeable inserts block for different chair backrest versions. Backrest inserts can be easily changed on the machine, we are also familiar with PC transparent chair with gas injection, various monoblock chair moulds with armrest or without

 Mould running cycle time  Mould service life guarantee  Parting Line finishing  Wall thickness  How to make chair moulds with less weight but strong enough  Stack ability  Air venting on the backrest  How to keep chair mould finishing long lasting.

 If the cooling water temperature is from 8 to 12 centigrade degree, if the chair weight from 1700g to 2400g, the cycle time should be 35s to 50s. If the machine plastic melt and injection is with accumulators. Please check how they make the cooling channel? If the cooling channel is extra in and out? If the cooling channel is one according with the chair shape?

 Many people will say that they will have one millions guaranteed. But God now how can they guarantee. The guarantee for a mould run 1 million shorts without any flashes? Because if you accept to cut the flash by your workers heavy labor, I think you can use this mould for 10 millions shorts. 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.

Sharp edge on the chair is dangerous, in order to avoid the sharp edge, we have to do many points during the mould manufacturing.  Chair mould parting design is correct or not.  The cavity and core thickness is enough or not.  How you make the CNC milling the cavity and core? One stage finishing or several stage finishing? Normally, we need 3 stages finishing. From rough milling to steel hardened, after hardening, take the 2nd stage milling, we call it half precise milling, normally we leave 0.3mm, Then make the steel stress releasing, after this we do final precise milling. When in this time, the machining operation is very important. we have to use cooling on the milling area, we have to be sure that each cutting, the depth will not bigger then 0.08mm. All these are because of the steel will be deformed when milling and after the hardening. The deforming will cause the cavity and core’s fitting are not accurate, there will be a lot of hand works on it. By hand works on the parting area, you can never work out a perfect parting line.

 Hand working on the parting line also be one of the reason 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 seriously when it is need. As because the uneven thick will caused the injection not balanced and also will caused the cooling time not even. This will effect the injection speed slow down and also will caused the shrinkage marks. If the CNC milling is too rough, you can never get a chair with thickness even.

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

 When starting make the plastic chair design, we have to consider the weight and the strength. You can make the bottom area be strong enough by add more ribs. But how about the leg, backrest 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, as you are using a material with MFI 4 or Max. 6.

 For some chair backrest design is very complex, there is a lot of material jointing line, and some air can not venting out when material filling and flowing. For this reason, you need to analyze by mold-flow maybe, and there are a lot of area need air venting built in the mould.

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

 Sino Mould Co.,Ltd  Wendy Lu :Sales Engineer     Skype: sino.holdings.group-007   Tel: Sino Mould is the leading chair mould manufacturer in china, we has developed more than 500 sets chair moulds during these years. If you need a high speed, long time and nice finishing chair mould, please come to us. We are sure you will be satisfied. For more plastic products moulds information, please kindly refer to our website: And Sino People always warmly welcome your visit to review our factory. Looking forward to start our long term business cooperation now!!

 DAKUMAR Machinery is one of our Sino Holdings Group branch company, which is one of the Chinese leading innovator for plastic injection molding machine researching and developing.  DAKUMAR has established service center in Brazil, Mexico, South Africa, Turkey, Israel, Russia...in order to make better service, we are negotiating with many oversea professional team to establish more and more service centers and partnership in different countries  For more information, please kindly visit our website or contact with me. Welcome your down visiting !!!!!!!!!!