3 Reasons DFM (Design For Manufacturability) Streamlines the Casting Process

05/22/2019 | Jason Schuh

Casting-1

These are demanding times. For a new product design to be considered successful today, its planning must also scrutinize the manufacturing process that will be used to build it. Modern designers look to specific design for manufacturing (DFM) guidelines to reduce costs while also simplifying how a product is produced, reducing design rework, and maintaining overall quality. You may also see the term design for manufacturing assembly (DFMA), too, which is the same principle.

Before we discover the ways DFM engineering streamlines the casting process, let’s briefly review DFM in general and the best ways to apply it. Simply put, DFM is the merging of product design and its production method. It can also apply to designing parts or components; the end goal is always to reduce effort and costs by simplifying and optimizing the process.

There are five areas of emphasis in DFM:

  • Process
  • Design
  • Material
  • Environment
  • Compliance/Testing

The key to DFM’s effectiveness is implementing it early in the process because as design progresses, changes become more and more expensive and difficult to implement. Early design changes are simply quicker and cheaper to execute.

DFM calls on all stakeholders to challenge the design, looking at it from all angles and at all levels, from component to holistic. This ensures the design is optimized and simplified, which reduces the time and inventory required to make the product.

Maximizing standardization not only reduces material inventory (and costs), it simplifies scale-up needs later. Scrutinizing the physical environment can help reduce the number of assembly operations required, so setup time drops as workflow improves.

Compliance and testing are critical, especially with complex shapes. An error in alignment can damage parts and/or equipment, hurt productivity, or perhaps shut things down altogether. Now that we’ve reviewed why DFM is important, let’s explore how it ties into casting.

The casting process provides unique opportunities and challenges.

Although casting is one of humanity’s oldest manufacturing processes, it’s still the method of choice for many industries. The advantages of casting vary as much as the kinds of casting processes, each with distinct design and manufacturing guidelines. Let’s briefly look at what casting is in the metalwork field.

Different metal casting processes involve pouring molten metal of various types into cavities formed into distinct shapes. Once the metal solidifies, the cast is separated from the mold. Casting makes intricate metal commercial and industrial products that, without casting, would be too complicated and costly to produce.

At its most basic, there are two types of casting. Non-expendable casting means the mold can repeatedly be used (permanent mold casting and die casting), with the mold cavities being made of metal. During expendable casting, the mold is broken away and discarded after only one use, such as with sand casting and plaster casting.

Different casting methods include:

  • Aluminum Die Casting
  • Sand Casting
  • Investment Casting (modern version of lost wax casting)
  • Permanent Mold
  • Lost Foam Casting (Aluminum & Iron alloys)

Although each method provides its own unique fabrication benefits, implementing DFM principles helps streamline any casting metal method.

3 reasons DFM streamlines casting

Reason 1 — Calculating Upfront Costs

In general, design decisions make up 70% of a product’s manufacturing costs. The other 30% are production decisions (process planning and tool selection). By focusing on optimizing design, a reduction is realized in the cost of manufacturing.

Using DFM methodology allows design engineers to identify design features that may be expensive, extremely challenging, or simply unattainable early on — at the design stage — so producibility is assured. DFM can also optimize casting steps, increasing manufacturability as it also maintains functionality.

Reducing upfront costs also includes minimizing the total number of product parts. This immediately reduces the material amount needed and assembly required. Fewer parts also means fewer resources needed for production, labor, engineering, and shipping.

Reason 2 — Scaling Up

A common casting struggle is scaling up from prototype (low volume) to production (high volume). Using DFM methods helps streamline production scale-up. When implemented at the beginning of the cycle, it reduces redesign, boosts product quality, and cranks up time to market.

Also consider high-volume production assembly issues. Handling castings involves specific positioning and orienting, and even assembly direction makes a difference. DFM thinking takes into account these labor assembly issues early to make high-volume execution easier.

Reason 3 — Considering Part Cost

DFM helps engineers make sure parts don’t require expensive secondary operations, which can make up as much as 80% of a component cost. That’s why many of a part’s tooling and casting needs and costs are explored during the casting design stage. This prevents rework at the caster and reduces time, both in manufacturing and time to market.

As the number of parts increases, total cost to fabricate and assemble rises. Plus, adding design documents and manufacturing processes drives costs higher. However, when the number of components is reduced, inventory costs related to purchasing and stocking drop.

Is casting even right for your part?

A respected machining partner should help you compare both the advantages and disadvantages of different types of molding processes. The proper selected casting method should be best-suited for a particular production run.

Stecker Machine Company is uniquely qualified to be a casting selection guide. Engineering expertise and quality checks are built into our process. Rapid prototyping and testing maximize part performance before production. Insight on casting and machining designs is shared far before launch. Advanced product quality planning (APQP) meetings are held. Plus, our solid, long-term relationships with more than 60 quality foundries mean our customers enjoy a reliable supply, knowing we’ll meet their deadlines.

When it comes to design for manufacturing (DFM) streamlining the casting process, there’s always more to explore. Stecker is ready when you are.

 

Jason Schuh

About the Author

Leading Stecker Machine's Sales and Engineering team, Jason enjoys solving customer challenges. As Account Manager for one of SMC's largest customers, Jason is responsible for managing a significant portion of SMC's work. Jason started at SMC as part of the Engineering team. He also supervised Manufacturing teams for a while but discovered that it's difficult to explain concepts that came easy to him.

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