SMI is the world-leading thermoformer of highly aesthetic, complex medical device enclosures and products.
Founded in 1976 and headquartered in San Diego, CA, Specialty Manufacturing, Inc., specializes in manufacturing large, highly aesthetic, multi-part enclosures for the medical device industry. With a relentless focus on achieving the highest quality standards for various plastic forming technologies and CNC-machined aluminum tooling, SMI utilizes an innovative approach to meet the demanding, close-tolerance design requirements of our customers.
SMI supports all aspects of the manufacturing process through a wide range of services including:
- Design assistance
- In-house tooling
- Large part manufacturing
- Spectrum (two tone parts) proprietary in-lay process
- Thin gauge packaging
SMI’s proprietary approach to manufacturing allows for better design for functionality and aesthetic appeal. Our unique process allows for undercuts and snap-fit features to be formed into the parts which reduces the number of attachment features requiring screws and other hardware for physical attachment during assembly. This in turn reduces assembly time and fit issues, lowering the total cost of manufacturing.
SMI has been able to help customers:
- Reduce on-site cover assembly time by 75%, thereby saving valuable time and money
- Improve aesthetic appearance
- Garner numerous US and international design awards
SMI holds ISO 13485 certification. SMI’s commitment to high quality parts and innovative design has made them the most awarded thermoformer in the industry, with over a dozen design awards to their credit.
SMI has expertise in Pressure Forming, Vacuum Forming and Twin sheet forming.
An extruded sheet of plastic is secured in a clamp frame and brought into an oven to be heated to a formable temperature. The clamped sheet is then removed from the oven and brought between a pressure box and the tool. A plug assist may be utilized to pre-stretch the plastic sheet for parts with a deep draw to reduce the amount of material thinning that can occur. Vacuum pulls the sheet into or over the tool and pressure at up 85 PSI is applied to the backside of the sheet. After the part is cooled unrestrained in the tool, (leaving a part that is free of molded in stress) the formed part is then placed into a 5-axis CNC trimming station where the part is trimmed to its final dimensions.
In a twin sheet thermoforming process, two separate sheets of material are heated simultaneously. One sheet is drawn into a top tool and the other sheet is drawn into a bottom tool using a vacuum process. The tools are then brought together and pinched around the perimeter of the part. Air pressure is applied between the sheets, pressing each sheet into its respective tool. The result is a hollow part that is structurally rigid and cosmetic on both sides. It is worth noting that the plastics industry typically use the terms “twin sheet thermoforming” and “twin sheet forming” interchangeably.
Parts that need to be controlled and/or cosmetic on both sides are ideal candidates for the twin sheet thermoforming process. Doors, panels and lids are great examples of these types of parts. An additional benefit of twin sheet thermoformed parts is that they dampen noise and can act as a thermal insulator.
Vacuum forming is a simplified version of Thermoforming. With the vacuum forming process, an extruded sheet of plastic is heated until it is brought to a formable temperature. The sheet is then removed from the oven and placed over the mold. Vacuum is then applied and the part takes on the geometry of the tool or mold. An optional plug assist may be used to help maintain uniform wall thickness and reduce thinning for parts with deep draws. The sheet is then placed into a 5-axis CNC trimming station, where the part is trimmed to its final dimensions. Any necessary holes are also drilled at this stage, completing the product for its final use in the device it was manufactured for.