You’ve put a lot of work into your product design. Now, your blow molding supplier will help you make your product its very best. This may include alterations that ease the production process, solve structural weaknesses, or expand product functionality.
Here’s how your blow molding supplier optimizes your product design.
Aiming for symmetry
When your blow molding supplier creates a mold, it will be split into two pieces, right down the middle of your product. To facilitate part removal during production, the mold must open up to release the part. Because of this, it’s beneficial for a blow molded part to be symmetrical, if possible.
Symmetry has three main advantages:
- It speeds both the mold creation process and keeps tooling costs down compared to creating an asymmetrical mold or a mold that requires moving parts.
- It provides for even material distribution when the plastic is blown inside the mold.
- It facilitates the removal of the part from the mold.
If your part isn’t symmetrical, your team may suggest alterations to move it towards symmetry.
Minding the seam
The parting line seam is another design consideration related to the split mold. The two halves of the mold create a seam in the product. If protruding product features, such as tabs or hose connectors are needed, it’s best if they are positioned along this seam. It can cause complications and increase the cost of production when they are located in hard-to-reach areas.
The seam also requires a cosmetic evaluation since the areas where the plastic flash is compressed will be noticeable unless the design team specifically addresses that process characteristic. They will suggest alterations that will preserve functionality while keeping the part seam clean looking and strong for production.
Adjusting for wall thinning
The thickness of the wall of your product will vary. This is a normal feature of blow molded products. But, it can also be tightly controlled through a combination of design and processing techniques.
During the blow molding process, compressed air is blown through a parison (tube) of melted plastic. This flexible plastic stretches to meet the inside of the mold of your product. The deeper into the product you go, the more stretching and less plastic there is coating the mold. The result is a slightly thinner wall at the furthest ends of the product.
Most parts can accommodate some wall-thinning and still function normally. However, if strength in these areas is necessary, your blow molding supplier may suggest design alterations.
- Change the draft angles on the walls.
- Bring up corners or add chamfers to strengthen the corners while maintaining function and shape.
- Add more plastic to specific areas by programming the plastic parson or thicken the walls throughout the product.
In-mold or a secondary operation?
Simplicity and ease of use are high on everyone’s list of product goals. But, today’s products often require a sophisticated approach to make that happen. Typically, that means accomplishing as many functions in a single part as possible. Some functions are ideal for in-mold completing, and others are best suited to secondary work.
Whether your part requires features such as a single hole or a series of sprayer heads, metal or plastic threads, or embossed printing or simple labeling, or is a standalone part or a component in a huge assembly, it takes experience and analysis to determine just how far to push each technology.
Consistent and cost-effective in-mold finishing and secondary operations play a big part in the success of many products. A blow molder with mold-building, fixtures, and automation teams can make unbiased recommendations that will make a tremendous difference in cost and consistency.
Expanding the functionality of the product
Your blow molding supplier should have ideas on how to improve the functionality of your product.
If you have a unique design requirement, such as the need for a water-tight chamber or an isolated rotating part, your designer may suggest four or five mix-and-match solutions to yield optimal results.
Looking for more on improving your product? Check out our blog on how to design a successful blow molded product.