High Pressure Injection Molding

20/20 Custom Molded Plastics, LLC has become home to an ever expanding fleet of high pressure injection molding machines. As of 2015 our capabilities were limited to machines of 375 tons of clamping capacity up to machines of 725 tons of clamping capacity. Today we range from 375 tons up to 6,750 tons. The newest addition to our high pressure fleet is a machine that has 6,750 tons of clamping capacity and two injection units. Our high pressure presses are housed in a brand new state-of-the-art facility, adjacent to our low pressure structural foam plant in Holiday City. This state-of-the-art facility has been designed and built based on the decades of experience we have in the industry. These machines are serviced by a 75-ton and a 125-ton overhead crane, as well as a team of professionals capable of “Thinking Big!”.

Frequently Asked Questions

How much clamp tonnage does my part need?

Clamp tonnage is set by the part’s projected area, which is the shadow the part casts looking straight into the mold, not its surface area or its weight. The multiplier applied to that area varies by resin, and a multi-cavity tool multiplies the total. 20/20 Custom Molded Plastics confirms press size against your actual geometry before tooling is committed.

What limits how large a high-pressure molded part can be?

Four specs set the ceiling. Clamp tonnage limits the part’s projected area, shot capacity limits how much plastic can be injected in one cycle, the spacing between the press tie bars limits the physical size of the mold, and daylight (the maximum opening between the platens) limits how deep a part can be, since the press has to open far enough to clear the mold and eject the part. A part can clear one of these and fail another, so 20/20 checks all four against a specific press before quoting.

How are tolerances set on a high-pressure molded part?

High-pressure molding packs plastic into the tool under heavy force, so it holds tighter and more repeatable tolerances than low-pressure processes. What is achievable on a given part depends on the resin’s shrink rate, the size of the dimension, and the tool itself. Larger dimensions carry wider tolerances because shrinkage accumulates across the part. Call out only the dimensions that are critical to fit or function, since blanket tight tolerances raise tooling cost without improving how the part performs. 20/20 CMP personnel work with their customers to help determine reasonable expectations on tolerancing before the mold is built.

Why does high-pressure molding require steel tooling?

The tool has to survive repeated cycles under heavy injection and clamp pressure without deflecting, and aluminum will not hold up to that on a long life expectancy part. Steel costs more upfront and takes longer to cut, so the tooling lead time usually sets the schedule on a new program. That upfront cost earns itself back through long tool life and lower maintenance costs, which is why steady annual volume is what makes the math work. For lower volumes or very large parts, structural foam with aluminum tooling is often the better number.

Can 20/20 quote the same part in both high pressure and structural foam?

Yes. 20/20 Custom Molded Plastics runs high-pressure injection molding alongside low-pressure structural foam, structural web, and gas assist, with both high-pressure and low-pressure processes available at the Holiday City, Ohio and Bluffton, Indiana campuses. A part that sits near the line on size, wall thickness, or finish can be looked at both ways before tooling is committed, which is the point where the decision is still cheap to change.

What do you need to quote a high-pressure part?

A 3D model or part print is the starting point. Quotes move fastest when they also include annual volume, the resin or the performance the part has to meet, which dimensions are critical, any assembly or finishing required, and whether tooling already exists. 20/20 reviews the geometry, flags anything that will cause trouble in the mold, and returns a molding estimate.