Ji-Horng Plastic Co., Ltd. Plastic Injection Molding: Common Plastic Molding Pressure
What is Clamping Force?
"Clamping force" is the average pressure exerted on the mold in order to resist the strong pressure generated by injection during plastic injection molding. Appropriate clamping force can ensure that the mold is not stretched open, thus avoiding the occurrence of burrs and flash in the finished product, so it is very important to select a machine with corresponding tonnage for injection.
How to Calculate Clamping Force?
Formula: F (Clamping Force in ton)= S (projected product area, in cm2) x p (cavity pressure from standard plastic pressure tables, in ton/cm2) x K (safety factor, 1.~1.2)
Common Plastic Injection Pressure
Below please find common plastic injection pressure from the form:
| Abbreviation Name | Full Name | Average Injection Molding Pressure (Ton/cm2) |
| ABS | Acrylonitrile Butadiene Styrene | 0.30~0.40 |
| AS | Acrylonitrile Styrene | 0.30~0.40 |
| EVA | Ethylene vinyl acetate | 0.25~0.35 |
| HDPE | High Density Polyethylene | 0.30~0.40 |
| LDPE | Low Density Polyethylene | 0.25~0.35 |
| PA6 | Polyamide(nylon) | 0.35~0.45 |
| PA66 | Polyamide(nylon) | 0.40~0.50 |
| PBT | Polybutylene Terephthalate | 0.35~0.40 |
| PC | Polycarbonate | 0.40~0.50 |
| PMMA | Polymethyl Methacrylate | 0.35~0.50 |
| POM | Polyacetal | 0.35~0.45 |
| PP | Polypropylene | 0.25~0.35 |
| PPS | Polyphenylene Sulfide | 0.25~0.35 |
| PVC(soft) | Poly(Vinyl chloride) | 0.25~0.35 |
| PVC(rigid) | Poly(Vinyl chloride) | 0.30~0.40 |
| PS | Polystyrene | 0.25~0.35 |
| TPU | Thermoplastic polyurethane | 0.50 |
The Consequences of Improper Clamping Force
Clamping force is too low
- Burrs: The pressure inside the mold cavity is greater than the clamping force, and the raw material overflows from the mold cavity, resulting in burrs.
- Inaccurate dimensions of molded products: molded products are supported and dimensions are incorrect
Clamping force is too high
- Reduced mold life: The mold is subjected to excessive clamping force, thus reducing its life
- Reduced machine life: In addition to the mold being harmed due to excessive clamping force, it may even affect the life of the machine.
- Poor mold exhaust: Too much clamping force will lead to poor exhaust, insufficient material filling, and even burn spots.
Related Article:
Plastic molding method: Injection molding
Plastic Injection Molding: Defects and Solutions
Plastic Injection Molding: Mold Design - Chinese-English Comparison Table
Plastic Injection Molding OEM/ODM Service
Ji-Horng is a professional plastic injection factory in central Taiwan with rich experience in customizing plastic parts. If you have any needs for injection molding molds, please call or email us.
The contact information is as follows:
Tel: +886-4-8355057
Fax: +886-4-8355059
Email: service@ji-horng.com.tw
Plastic buckle professional manufacturer
In addition to injection molding, Ji-Horng also provides existing products: thousand types of plastic buckles, plastic swivel hooks, toggle cord lock, side release buckles, webbing adjustment buckles, etc. If you have any needs, please visit the plastic buckle product page, or contact us directly to learn more:
Plastic Tri-glide: https://www.ji-horng.com.tw/slide-buckle-series
Plastic buckle: https://www.ji-horng.com.tw/plastic-buckle
Cord stopper: https://www.ji-horng.com.tw/cord-stopper
※This article is for academic reference only. We do not provide plastic raw materials for sale. If you have injection molding needs, please feel free to inquire. Thank you!