Use Pressure Forming to produce superior electronics housings

How Profile created an award-winning AC Motor Drive cover

Covers for low-to-medium voltage industrial AC drives are usually made of metal. Thermoformed plastics offer OEMs an opportunity to improve performance while reducing weight and cost.

However, even in indoor applications, these covers need to provide proper venting, shield against electromagnetic interference (EMI), and resist the spread of possible flame. They also need to support product assembly and mounting.

Challenge: How Do You Overcome Multiple Design Difficulties?

A multinational industrial automation systems provider was considering thermoforming covers for two AC drive models. A key design requirement was fire-retardant plastic with specific UL 94 flame ratings. Inside, the covers also needed to meet C2 EMC certification requirements.

The project also presented several Design For Manufacturing (DFM) challenges. In addition to detailed cosmetics, the cover required an isolated area for proper venting.

The drive unit offered little space for internal components, let alone fasteners for the cover. Creating a perimeter undercut with a smaller-than-normal radius was the mounting solution. However, the deep draw ratio of the part made it more difficult to achieve a uniform wall thickness.

Solution: Partner with a Value-Added Thermoformer

Pressure forming could achieve cosmetics with the level of formed-in details that the customer wanted.

Profile’s experience helped them create a perimeter undercut design for mounting the cover to the base unit while achieving a maximum wall thickness in specified areas. Despite the tight radius required, the engineering team was able to maintain part thickness – even with a deep draw ratio.

The team also leveraged their material expertise, recommending the use of KYDEX® T brand thermoplastic with a .250” starting gauge. This matierla features UL 94 V-0 and UL 94 5V flame ratings. It also supports deep draws with less wall thinning.

Profile’s value-added DFM assistance also resulted in a vent design and dimensions that met all requirements. The customer chose small fasteners that fit the design. For EMI protection, special masking was required for specific areas. Profile’s painting partner used electrically conductive paint on the inside.

Results: Award-Winning Thermoforming    

The AC motor drive covers that Profile produced met all the project’s requirements. From DFM assistance and material selection, to toolmaking, expert thermoforming and EMC coatings, Profile delivers greater value for industrial customers.

This project also won an award from the Society of Plastics Engineers (SPE) Thermoforming Division.

Learn more about EMI protected thermoformed electronics housings.