PT Blog

A project initiated by an existing customer prompted injection molder Pittsfield Plastics Engineering LLC (PPE) to boost its large-part molding capability. Back in November, PPE added a 1204-ton injection machine with a shot capacity of 155.6 oz to its plant in Pittsfield, Mass. PPE’s investment in the Haitian Jupiter III (JU10800 III) from Absolute Haitian is the latest in a series of upgrades the molder has made over the last five years. The machine cell is equipped with a CW15-2000 servo robot from sister company Absolute Robot. Before this purchase, the largest press at PPE’s facility was 730 tons. 

PPE is an ISO 9001:2015 certified company, housed in an updated 64,000 ft² facility with 25 presses. It runs three shifts in a 24/7 operation. Its molding operation is supported by a fully equipped tool room. PPE has also recently ramped up its R&D efforts with a new technology center housing a gamut of testing machines. In addition to custom work, PPE has a proprietary line of spools for the wire-and-cable and textile industries.

Regrind can be a tremendous asset, a costly liability, or just an afterthought taking up shelf space. For plastics processors who use or produce regrind, steps should be taken to track and manage it like any other material. However, this can require time and effort; and is not necessary in all cases. Here are a few questions to help you determine whether tracking regrind is right for your operation.
 

For many processors regrind is a cost-saving recipe ingredient and added revenue source. In addition to saving expensive virgin resin, plastic processors may allocate the cost of regrind processing as part of product costing. They may also deduct the cost of what they receive back from the recycler. Others may simply charge the full cost of the virgin raw material and processing time to the job and recover regrind sold to the recycler as a bonus.

Hygroscopic polymers such as PET, ABS, TPU, PC, nylon, and many others absorb moisture from the surrounding environment. These types of polymers have a polar molecular structure that attracts the polar water molecules from the air. If these materials are processed with high moisture content, the high temperature causes a chemical reaction (hydrolysis) that breaks the polymer chain into smaller molecular weights. Prior to processing, hygroscopic materials must be properly dried to prevent processing issues and poor end-product performance.

Conducting a drying design of experiments (DOE) will ensure your polymer is properly dried every time. Performing a DOE saves significant time because you get the most information with the least data possible and can determine direction and magnitude of each process input. The power of a DOE is the ability to use a simulation model to change input settings and predict the outputs. This will enable to you to establish the optimum input settings that are most efficient at the lowest possible cost. Instead of following datasheet recommendations, develop the process based on scientific data. You will be surprised by how much time and cost savings you will gain by conducting this simple experiment. 

Transferring a process from one machine to another is a daunting task. There are a multitude of parameters to set, and the setup sheet for one machine will not necessarily work on a different machine. Once you get a press to start making good parts, you make up a setup sheet specifically for that mold in this machine. But this setup gets repeated every time the mold is scheduled into a different machine. The hassle, time and costs are significant. 
 

So how come a setup sheet does not apply to all machines? Before we answer this question let’s take a step back and look at the big picture. We have a large and mature processing industry. It might be the third largest manufacturing sector in the U.S. Molding shops use setup sheets for their processes. Since the industry is large and we all are trying to document the process and make it repeatable, why don’t we have a standard, universal setup sheet? We all have the same issues. Think of the scope of this subject: If we estimate that there are 16,000 molding shops, my bet is there are 16,001 different setup sheets. Does this make sense?

Devolatilization is the process by which unreacted monomer, solvent, water, dissolved gases, or other undesirable volatile contaminants are removed from a polymer melt or solution. It is a mass-transfer process driven sdiffusional variables, with the design of the machine impacting both of these parameters. It is driven by superheating the volatile component, followed by exposing the melt or solution to a rapid decompression.