KMC Engineers Design for Manufacturability to Trim Medical COGS

This is the second in our Reducing Medical Manufacturing COGS series detailing how KMC Systems reduces customer Cost of Goods Sold during the medical device manufacturing process through its Design-for-Manufacturability software. The DFMA® software is just one aspect of KMC's cost-saving Design for X (DFx) process.

By Tracy Mallette and Bob Evans

KMC reduces your medical device manufacturing Cost of Goods Sold by coupling the knowledge of our experienced engineers with our Design-for-Manufacturability software.

DFM reduces your COGS

Design for Manufacturability (DFM) focusses on reducing the cost of manufactured parts.

KMC Systems Senior Principal Manufacturing Engineer and Manager of the Manufacturing Engineering Group, Dan Frisbie, explains that DFM reduces the cost of parts by:

  • simplifying and reducing the number of parts: The less parts ordered, the less can go wrong. Standardizing parts also makes the device easier to assemble and reduces assembly time.
  • designing for ease of fabrication: Minimizing the number of fabrication set-ups (needing to rotate or invert the part) makes the fabrication process quicker and easier. Also, avoid unnecessarily tight tolerances to reduce the number of rejects and inspection time. 
  • using near net shapes for molded and cast parts: Molding a part to a near-finished shape rather than starting with a block of raw material each time minimizes machinery and processing effort.
  • implementing poka-yoke: As mentioned in the previous DFMA post, designing parts so they can't be assembled the wrong way saves time and money while preventing malfunction.
  • designing for part orientation and handling: Avoiding quirky part shapes that get stuck together will minimize manual effort.

KMC applies all of these DFM principles to reduce the cost of medical device manufacturing. Read on for the how.

Experienced medical device manufacturing engineers design for manufacturability for customer cost-savings

The Boothroyd Dewhurst DFM software that KMC uses helps engineers design, or redesign, lower-cost parts, and gives them the data necessary to effectively collaborate with suppliers.

When KMC participates in a manufacturing transition project, we use the software to determine the should-cost for critical and high-cost BOM components. Many times in a transition project, there is not adequate time to redesign or re-tool for a more efficient manufacturing method. KMC Mechanical Engineer Will Brooks says, "there’s no chance for us to go back in time to figure out how to reduce the cost before we need to buy parts." In that case, we use the software to help us target the should-cost so we can work with our suppliers to obtain the best pricing.

When KMC designs your medical device, we're able to use the software earlier on in the process to Design to Cost - one of the key benefits of the KMC360® total medical device product life cycle program. Brooks explained that with a KMC Systems medical device design project, during the design process, we incorporate our manufacturing-process knowledge (especially for parts that require tooling) as well as how to meet the design requirements, focusing on a cost target for each part.

For instance, if we can meet the design intent with more than one type of plastic, we'll choose the most cost-effective one.

Using the DFM software

Some of the options in the Boothroyd Dewhurst DFM software used by KMC
Here are some of the factors our engineers enter into the DFM tool that help calculate a medical-device part's should-cost.

Engineers select the manufacturing fabrication process and material for a part in the DFM tool, which then generates a list of questions, or operations, to choose from based on that initial information. For example, you can select a drilling operation, enter in the dimensions of the hole you need to drill, and the tool will give you a cost associated with that operation.

Brooks takes us through using the DFM software and some of the cost-saving techniques associated with it.

First, he picks a machine cut from round bar stock and selects a material. For this example, aluminum.

The software then presents additional fields of information to be populated using the pull-down menus:

  • What is the cutoff method for the aluminum round bar stock?
  • What is the hardness of the aluminum alloy chosen?
  • What is the optimum manufacturing batch size?

Understanding the manufacturing process is key. Even details like whether the aluminum round bar stock is purchased in 10-foot or 20-foot lengths affects the manufactured-part cost.

The software gives default values for labor rates and standard operation rates for different machines. These default values are based on country averages, so it's necessary to customize the values for your region. For example, Brooks said, machine shop labor in New England costs more than in Alabama.

Once the fabricated-part data is ready, there’s a library of operations available to choose from. For our example, Brooks selects a generic CNC, a process the software knows requires programming for that machining operation and assigns a value based on the cut complexity. 

The machinery and operator rate has a big effect on cost, so engineers should be familiar with the machining processes in order to select the most efficient process. The DFM software tool evaluates manufacturing fabrication processes and operations so engineers can select the most efficient and cost-effective one. If one operator can program a machine, then go watch another, that cuts the cost in half.

The software's operation library contains most of the machine operations available, but if a specialized operation is required, engineers can customize their own within the software.

The software also covers post-manufacturing operations, like polishing and welding.

Engineers can look at the cost of each individual operation, as well as overall cost.

Communicating with medical-device parts suppliers

The DFM tool gives our engineers the data to back up the information they're communicating to suppliers and helps them understand the limitations of suppliers to save time and money on manufacturing medical-device parts.

It's not enough to look at the software's should-cost analysis and expect suppliers to meet that price. Engineers need to be able to dissect each aspect of the process to understand why a part might cost more to manufacture and decide the appropriate action to take from there. 

Brooks explains that the tool is helpful for looking at every operation step in the manufacturing process. In your analysis, you might select what you think is an efficient process and overlook the need for special fixturing that will increase tooling or machine set-up time. Communication with your suppliers is key to understanding the effects of part features on manufacturing costs.

Our manufactured parts suppliers are open-minded about this new approach to controlling COGS. They understand that open and honest discussion to collaboratively find the best solution for our customers benefits all. It does require effort, but investing in relationships to establish a strong supply chain is key to maintaining control and reducing COGS.

Engineering experience is key to COGS-saving success

It's not enough to just buy the DFM software. For successful implementation, skilled and experienced engineers must apply their knowledge to the software.

With more than 30 years of medical-device manufacturing experience, KMC Systems engineers have the knowledge necessary to control and manage COGS.

"You have to have every detail of the operation in order to come up with the most accurate should-cost analysis," Brooks said, "We have guys who’ve been in engineering for 20-25 years and have a lot of machining background. A lot of them have their own [fabrication] tools at home, so they know a lot."

Applying our experienced engineers' fabrication-process knowledge to the Design-for-Manufacturability software allows us to maximize the tool's capabilities and significantly reduce your medical device manufacturing COGS

Consideration of manufacturing process should coincide with a detailed design process - and that requires experience. If a part design has been completed, our experienced engineers can identify opportunities for ease of manufacture using cost-effective processes.

Contact us for more information on KMC's medical device manufacturing services. 

The next post in our Reducing your COGS series will detail KMC's process for assembling more cost-effective parts for your medical device.

Topics: Medical Product Manufacturing, KMC Systems, medical device design, medical device manufacturing, dfm, design for manufacturability, Reducing your COGS, medical manufacturing COGS, medical manufacturing