QT Manufacturing announces the addition of a new Engel ES700/250, 250-ton plastic injection molding press to our lineup. This doubles the clamping pressure and increases our capabilities to produce larger parts with our previously largest press, a 123-ton Nissei. With press sizes ranging from 30-ton to 250-ton, we offer broad capabilities to produce small to medium-size and larger injection molded products. View a list of our press sizes and capabilities here.
Injection Molding Machine Tonnage/Clamping Pressure
Plastic injection molding machines are classified by tonnage, which specifically describes the clamping pressure or force of the press. For example, a 110-ton press is typically rated for 110-ton clamping pressure. Clamping pressure ensures that the mold stays tightly closed during the molding process. Too little or too much pressure can result in quality defects such as flashing which occurs with excess material surfaces on the edge of the finished product.
Material and Mold Flow Index (MFI)
Clamping pressure also affects the viscosity of raw resins. The mold flow index (MFI) is the temperature which indicates a thermoplastic resin’s ideal temperature for ease of flow. The greater the MFI, the more tonnage/clamping pressure is required. Certain materials may require a higher injection molding pressure available only in a higher tonnage press.
Projected Part Area
If a four cavity mold produces four parts which are 5” x 5” x .2” square, the part has a projected area of 100 in.² (5” x 5” = 25 square inches, times 4 cavities). Total projected area directly affects the clamp tonnage required. If molding with a polypropylene with an MFI of 10, typically 2.5 tons per square inch of projected area is required for clamping pressure. At least a 250 ton plastic injection molding press would be required to mold these parts with this 4-cavity tool.
Mold Dimensions and Shot Size
The mold dimensions, shot size and the size of the part, are important considerations when choosing the right size of press. Sometimes the part size may seem to fit with a smaller machine, but complex geometries in the mold may dictate a larger size of press is required. The part size must conform to all machine specifications such as mold thickness, platen size, machine shot capacity and clamp stroke.
Plastic injection molding is the preferred manufacturing method to produce a wide range of products from household goods to consumer electronics, automotive parts, telecommunications components, aerospace products and more. The next time you brush your teeth in the morning, take a drink out of a water bottle, toss a frisbee, pound your keyboard or grab your cell phone, you can thank plastic injection molding for bringing you convenient products you use every day.
Injection Molding and Mold Making Capabilities
QT Manufacturing offers plastic injection molding and mold making capabilities with mold design and a modern tool room with precision CNC machining capabilities. Our experienced engineers work with customers to provide high-quality tools that produce consistently high quality finished products. Our injection molding presses include:
- 30T
- 40T
- 50T (2)
- 60T
- 66T (2)
- 85T (4)
- 100T (2)
- 123T
- 250T
You can count on QT Manufacturing for high-quality injection molded components with mold design, new tool builds and on-site tool repair with preventive maintenance capabilities.
QT Manufacturing is ISO9001:2015 and AS9100D rev D certified, following a strict quality policy to ensure high-quality products and services. We continually invest in capital equipment and improvement activities to reduce costs and improve quality. Contact us at (972) 221-0537 with any questions and to learn more about our new 250T plastic injection molding press.
