JANUARY 31, 2021
Uncii is a Colorado based startup company that designs and develops automotive rack attachments for different sporting goods equipment like skis, boating paddles or oars.
A local plastic injection molder referred Uncii to us because the 3D CAD model produced for them was not correctly designed for the plastic injection process. Uncii had already developed a visual look to their product and had tested several 3D printed prototypes to confirm the functionality of the design.
In our first meeting we did a review of their 3D CAD model design and discussed the issues it had in relation to plastic injection molding. The part’s design is one piece but intricate and requires a five-piece mold. For simplicity and durability, we normally try to make plastic part designs from two-piece molds. Each piece of a mold is pulled away from the part in a different direction, adding to the cost of the mold, reducing the number of parts that can be made in an hour which increases part cost. But for Uncii, this approach of having a five-piece mold eliminated the need to have multiple molds, eliminated any assembly labor costs and increased the parts total strength.
So, the first order of business was to develop a plan of which areas of the part would be formed by which of the five mold pieces. Once that was sorted, our next obstacle was to design the plastic part to have a relatively constant wall (material) thickness throughout. There can be some variation, but the more constant the better. At the same time, we are also looking at how to prevent sink marks where one wall may terminate into another and create a local thick mass of material. The thicker mass will shrink more than the surrounding material and make the outer surface of the part look sunken. We try to avoid this as much as possible to not affect the cosmetic appearance of the part. Sometimes sink marks able to be hidden by adding texture to the surface of the part.
Because we are an Industrial Design Company, we had to tidy up some of the visuals of the original plastic part’s design. We sorted out the bottom ribs to be more uniform and added support ribs to the two large cavities so the plastic would not sink inward on these large flat surfaces, thus preventing what is called the “Oil Can” affect. Adjustments were made to the front handle to improve the molding process and to persevere the original styling intent. To get the colored logo on the sides of the part we created a raised logo feature so that the part could be pad printed easily, eliminating the need for secondary labels that tend to get affixed crooked.
After we developed the new 3D CAD model, we continued to work with Uncii and the manufacturer to answer questions and help Uncii understand some of the options the manufacturer was seeking direction on from them. We also stepped in at times to help the manufacturer understand design intent and why some items could not be altered from the design that was given to them. In most cases we were able to offer other solution that achieved what the manufacture was trying to do to improve the plastic injection molding process.
Covid has affected the ski industry and therefore the sales of Uncii ski attachments, but they are expecting things to improve and are already developing other designs for their product line-up.
