The Importance of Design Engineering in Plastic Injection Molding

Before you can manufacture a plastic part you need to have a solid design in place. Once done, you can build an injection mold to meet the product specifications. 

The role of the Design Engineer is critical in this process. They assess the part design and make modifications and recommendations based on key product requirements including product usage and function. The engineer will need to know:

• How will the part be used? Is it a standalone product or a component of a larger assembly?
• What are the dimensional and tensile requirements?
• Does the part need to withstand elements, pressure, chemicals?

A plastic injection mold design is built with these criteria in mind. Mold cavities, vents and gate placement will vary based not only on the part design but the type of resin as well. Taking all of these manufacturing factors into account is a challenging task and one that requires a strong knowledge base, not only of mold design but the injection molding process as well.

We took some time recently to talk to one of our Design Engineers, Mike Baranoski, a Rodon employee for 24 years. Mike and his wife have three boys. Their middle son, Matt, will complete this year in Brazil as a member of the U.S. Olympic Cycling team.  We asked Mike to give his perspective on the plastic design process:

Can you tell me a bit about your background?  How long have you been with the company, your experience, and how did you become a Design Engineer?

My background was in tool and mold building. I started working in the trade at 17 years old and finished my mold maker’s apprenticeship at 20. In the years following, I changed jobs several times to try to get as much experience as I could. I will have been at Rodon for 25 years early next year. I started as a mold maker, then a shop foreman and for the past nine years, I’ve worked in the design department.

Can you take us through the process you use when a new design idea it presented to you? 

The first thing I do when I receive a new part or concept is to make sure that the part is moldable. I recommend changes to the customer to make the part and tool as simple and robust as I can. The simpler the tool, the less they will have to pay for it. The stronger the tool is made, the less down time Rodon will have, and the more dependable part delivery the customer will have.

Can you give us an example of a difficult design problem and how you and the team resolved it?

We have had several design challenges over the years. Most are solved by analyzing the parts real function and modifying it to achieve those requirements while making it mold friendly.

What are some of the most common problems you face when designing a high-production mold and how do you overcome them?

The common problems are always gating, venting and cooling. Each can be changed or altered as needed to produce a part that will meet the needs of our customers.

With more products transitioning from metal to plastics, how has that changed the engineering of the parts?

The demand requirements of plastic parts have increased over the years, and so has the selection of materials that we use.   From glass filled to different durometers of the plastic, we can usually find a material that will meet the customer’s needs.

How has your role changed in the past ten years?

I was the tool shop foreman before I moved into design. That gives me an invaluable view of tooling and its design. I constantly alter tool designs to make it how I would like it if I were building it myself. I was also able to see firsthand out in the shop what concepts failed and what concepts ran for years of maintenance-free operation.

With the advancements in 3-D printing and new polymers and additives, where do you see the future of plastic injection molding?

3D printing is still in its infancy. Eventually not only will you be able to print a working model of your part but you will be able to print the mold to manufacture high-volume injection mold parts. They already have a hybrid process that combines 3D laser sintering and high-speed milling to produce an accurate cavity. The future is very exciting when it comes to this kind of innovative thinking.

How do you address quality issues during the production testing phase of the process, after the mold is built but before full production?

Quality isn’t something that is checked only at the end of the process. We have double checks set up along the way. Each design is put through a design review process and is checked again by our CAD team make sure nothing was missed. Each department in the shop checks the cavity quality throughout the entire manufacturing process.

What do you think we’re doing at Rodon that makes us stand out from the competition?

Rodon’s customer service is what separates us from our competitors. Not only up front but also when a part modification is required. With everything under one roof, the changes can happen fast, and the customer receives their parts with minimal downtime.

All of the Design Engineers at Rodon have a wealth of experience not only designing molds but building them as well. This background gives our in-house team the ability to find creative solutions to even the most challenging design manufacturing problems. 

If you need high-volume, custom, plastic injection molded parts or if you have a metal part that you would like to convert to plastic, please contact us at sales@rodongroup.com or complete our RFQ form.