Our fourth quarterly project actually requires rotational molding, which is a process that Bo-Mer brought in house about 12 years ago. We are going to see how the main base of this high-end stroller is produced.

The process starts with a specific amount of resin, mostly a type of polyethylene, being poured into a hollow mold. For this job there are actually three graphics that are applied to the mold, which eventually adhere to the resin during the forming process. Once the mold is clamped and sealed together, you will see that the mold begins to rotate as it gets sent into the oven. While the mold is in the oven, the material begins to soften and evenly disperse and stick to the walls of the mold.

The mold continues to rotate biaxially throughout the heating phase all the way through the cooling phase, which is about 50 minutes for this part. Each rotation, along with the correct speed, are critical in order to maintain an even thickness throughout the part. Once the part is cooled, it is removed from the mold and placed on a fixture to trim the part to size, as we use a hand router to remove all the excess scrap and produce the end part.

A little background on this job while the part is being trimmed- it was originally designed and manufactured for thermoforming with a weatherable ABS which worked well. However, the customer requires all of their products to have a lifetime guarantee, no questions asked. Due to continued wear over roadside curbing, the ABS would eventually become weak and break- therefore, an alternative process was required. After months of discussion, the product was redesigned for rotational molding using a weather polyolefin. In addition by going with this process, in-mold graphics could be applied. The process change in new product was a huge success. Once the trim up is complete, the part is then placed on the stroller to confirm it fits and is ready for the end customer. As we continue to utilize this process, we know we may not be the largest rotational molder out there. However, we strive to perfect the process and bring it to the next level.