Injection Molder Streamlines Quality Inspection

EVCO Plastics is a global injection molder based in DeForest, Wisconsin, with plants throughout the U.S. as well as Mexico and China. Since 1948, the company has produced parts for a wide range of industries including powered sports equipment, lawn and garden devices, agricultural and construction machinery, appliances and plumbing fixtures, medical and packaging machinery, as well as general industrial products.

The company has over 150 presses in the 28-3500 ton range, its own mold production and a metrology lab for quality evaluation.

EVCO performs ISO Class 8 Cleanroom, large part, thin-walled, metal-to-plastic insert, gas-assist, multi-shot and overmolding operations, plus in-mold decorating and labeling in highly automated and robotic facilities.  The company produces parts in various thermoplastic materials, ranging from basic polypropylene to engineering grade materials. The company currently employs over 1000 people at its nine locations worldwide and is a major player in the global injection molding sector.

Part of the EVCO strategy, according to the head of the metrology lab Rich Duval, is “…to have the ability to take a part, scan it, compare it to the CAD/CAM files, as early as possible in the process and to allow the customer to observe how the plastic product compares to the solid model.” Duval also notes that by using scanning technology and reverse engineering, the metrology team has been able to recreate the surface of tooling where solid models don’t exist and provide this data to a tool shop for steel revisions.

Romer arm and 3D scanning software scan an injection molded part, capture the data, compare it to the CAD file and make any adjustments needed to the mold or injection press settings.

Recently, owing to the volume of work coupled with the challenges of collecting and processing point cloud data in the lab, the EVCO team turned to Exact Metrology (Brookfield, Wisconsin) for assistance.

Exact VP Dean Solberg and his team of metrology technicians and application support specialists reviewed the EVCO scenario and provided several new Romer arms. One example involved the staff taking a damaged tool component and reconstructing the cogs on a machine gear. Once rechecked through design, a suitable alternative could be 3D printed. Duval note that the metrology solution proposed by Exact reduced inspection time in the lab and provided reverse engineering as an additional option to its customers.

Similarly, older molds used at EVCO are being evaluated with the scanning techniques for position of runners, pins, cores and other components. A solid model is produced from the scans to show auto-surfacing, solid model processing and solid model in-use characteristics. Often, reverse engineering from existing parts is also performed in the EVCO lab for production issue resolution or part validation.

While EVCO continues to use the conventional CMM technology in its metrology department, Duval notes his team of technicians has been able to “marry” the Romer arm and CMM technologies.

“This was possible, only because of the talent on the team at EVCO,” Solberg adds. In practice, the combination of the 3D scans with the bridge CMM plates gives the EVCO technicians and design engineers the necessary comparative data to resolve any issues that arise.

The data are also integrated with the output from the bridge CMM equipment to feed the point cloud.

Support from the Exact team has aided EVCO during this ramp-up of the new scanning technologies, according to Duval, who notes, “We had some lurking questions after the initial training session, but Dean was very pro-active and amended the training protocol to suit our specific requirements.  It’s produced a very positive outcome here.”

As a supplier to major OEM’s in many industries, EVCO is routinely expected to supply considerable part and production data to its customers, according to Duval.  “We are planning to utilize the Exact equipment to support tooling, as well, so there will be a seamless capture and transmission of data from part design through production here.

EVCO has also investigated further use of the Exact CT scanning services, though many of the very large parts produced, such as farm machinery housings, exceed the scan envelope of the CT equipment, presently.

One of the strongest abilities at EVCO is the company’s production of near-finish prototypes. These prototypes are often produced with conventional CNC machining or through the use of the rapidly expanding 3D printing technologies.

EVCO also performs fused deposition modeling (FDM), with and without carbon fiber. Exact Metrology provides 3D scanning techniques which produce the necessary data files such as STL that can reside in the “point cloud” for use by these advanced 3D prototype production technologies.  Millions of data points provide the 3D printing equipment all necessary information to produce highly accurate prototypes and concurrently anticipate challenges that might arise in the transition from design to tool to production, according to Duval.

The new metrology equipment used at EVCO is helping the company attain its stated goal of supplying world-class plastic products and assemblies.

www.evcoplastics.com