There are differences between the blister machine for CPET plastic sheets and the blister machine for ordinary PET sheets, mainly in terms of heating system, mold design, molding process, cooling system, etc.
| Category | Standard PET Thermoforming Machine | CPET Thermoforming Machine |
|---|---|---|
| Heating System | Suitable for conventional PET materials such as APET, RPET, GAG, etc. Use medium and low temperature heating (120-160°C), and infrared heating system to soften the sheet. | CPET (crystalline PET) needs to be molded at high temperature, and its glass transition temperature is as high as 220-260°C. A high temperature heating system (infrared + ceramic heating) is required, and the heating time is longer than that of ordinary PET to ensure uniform heating. |
| Mold Design | Suitable for cold molding, often using aluminum molds or hard steel molds. Mainly using negative pressure blister or positive and negative pressure molding, cooling after molding can be fixed. | High temperature resistant molds (such as special alloys or chrome-plated steel) are required to withstand the high temperature molding process. High temperature thermoforming + rapid cooling technology is used to ensure the stability of the crystal structure of CPET and improve heat resistance (CPET can withstand 200°C). Special surface treatment may be required to prevent CPET from sticking to the mold at high temperatures. |
| Forming Process | The sheet is heated to the softening point (120-160°C). Negative pressure blister molding or positive and negative pressure molding. Immediate cooling and shaping to ensure high transparency and rigidity. Punching, stacking and packaging. | The sheet is heated to 220-260°C (much higher than ordinary PET). High temperature pressing is performed during the molding process to ensure that the material is fully crystallized and improves high temperature resistance. Quick cooling (using cooling water system or air cooling system) ensures that the CPET box is shaped and reaches high temperature resistance (suitable for microwave heating). Punching, stacking and packaging. |
| Cooling System | Using general air cooling or water cooling system, the cooling time is short (within a few seconds). It is mainly for rapid shaping, and no special cooling process is required. | A stronger cooling system is required, usually circulating water cooling + air cooling to ensure that the finished product has a stable crystal structure. The cooling speed control is strict, otherwise the molding effect may not be good. |
Equipment applicability
Ordinary PET blister machine cannot be directly used for blistering of CPET sheets because:
- The temperature is not high enough to soften the CPET sheet.
- The mold may not be resistant to high temperature, affecting the quality of the finished product.
- The lack of a suitable cooling system makes it impossible to stabilize the shaping.
- CPET blister machine can be applied to ordinary PET sheets, but there may be problems with low efficiency or excessive heating system, so it is usually not recommended to use high-temperature models to process ordinary PET sheets.
Applicable market
| Material | Suitable Thermoforming Machine | Application Scenarios |
|---|---|---|
| Standard PET (APET, RPET, GAG) | Standard PET Thermoforming Machine | Cold drink cups, fruit & vegetable packaging, electronics trays, cosmetics packaging |
| CPET (Crystallized PET) | High-Temperature CPET Thermoforming Machine | Microwave food trays, bakery containers, high-temperature food packaging |
If your production needs are ordinary PET fruit and vegetable boxes, folding boxes, electronic trays, etc., you can use an ordinary PET blister machine; if you need to produce high temperature resistant food trays (such as food boxes heated in microwave ovens), you must choose a dedicated CPET blister machine, otherwise it will not meet the production requirements
