First, what is DFMA (Design for Manufacturing & Assembly)?
DFMA (Design for Manufacture and Assembly) is a design methodology that prioritizes both ease of manufacture and assembly efficiency. DFMA combines two concepts: Design for Manufacture (DFM) and Design for Assembly (DFA).
- DFM Definition: the process of designing products while optimizing material and production costs with the goal of producing a better product at a lower cost.
- DFA Definition: the process of designing products while minimizing assembly time by using fewer components that are easier to put together.
The crucial concept to understand with DFMA is that it seeks to optimize overall product delivery by making products that are both easier and cheaper to create and assemble.
9 DFMA tips to consider during design and engineering
The following are some of the general practices, considerations, and tips of DFMA design examples. You should use these tips in conjunction with engineering judgment-based technical experience as well as your company's standards and practices. Please note: not every optimization strategy can be covered in this blog, so we focused on high-level changes you can make to your design and engineering approach that are easy to apply.
- Avoid reinventing the wheel: Purchase off-the-shelf parts if possible
- Designing components from scratch that can be purchased through a supplier is often less expensive than creating custom parts. In addition, you will benefit from better quality control and be able to order in bulk.
- Avoid over designing your parts
- Maximize your material selection to achieve needed functionality while selecting a material that will get the job done. Weaker materials generally cost less when they have higher machinability since they have a faster machine run time and lower tooling costs.
- Consider the nominal raw material size from the start
- When selecting what stock you will machine from, it is a good idea to pick a commonly available size. Standard size materials are more accessible and have lower costs compared to uncommon sizes. For instance, purchasing a standard round bar stock size of 2", 2.5" vs a non-standard 2.375", 2.625" will generally result in a lower cost. In addition, designing for minimum raw stock material removal minimizes material waste and machining time during operations.
- Avoid designing mirror parts
- Design in symmetry can save time in manufacturing with less setup, stacked machining, and require fewer parts stored in inventory. In addition, parts that look the same but are functionally different often cause assembly issues leading to higher assembly and upkeep costs. For example, an assembler may cross thread a component during assembly ruining it and the threaded connection they are attaching it to resulting in slower overall production due to needed rework.
- Label for your audience.
Avoid having a high surface finish when it’s not needed.
- Don't expect a machinist to pull out a calculator to figure out a dimension from trigonometry on your drawing. For example, if a drawing has a length of X listed next to an angle degree dimension. A machinist will need to pull out a calculator to determine the Y dimension or calculate the coordinates from a bolt hole circle, etc. which can lead to an error. The goal is to make your design as easy as possible for the machinist to produce your parts to reduce unnecessarily wasted time.
Consider the production tools you have available
- Higher surface finishes require slower machining time and in some cases may require additional operations like honing.
Consider other manufacturing processes
- Using standard cutter tool size when given an option for machine availability (manual vs CNC) means you can avoid custom tooling. Custom tools cost more in general.
Always review, check, and double-check drawings for errors.
- The same component can often be produced through casting, forging, molding, or stamping. For instance, if I have a 16" cylinder that requires milling a huge area of material to make a piston, you may want to consider a casting approach. On the other hand, casting requires a higher upfront cost that may not be suitable for a prototype design or minimum production usage.
- 3D CAD modeling is a tool to aid design, while drawing is the contract between the purchaser and manufacturer. A clean and error-free drawing avoids confusion and reduces the chances of modifying the drawing, which would add cost for drawing revision.
A live and collaborative environment between the different stakeholders for interaction during the design phase is the main key element of DFMA. Remember, it's essential to engage with contractors, suppliers, design engineering teams, and manufacturers that understand the value of DFMA. This way, you can apply them to your standard processes to see benefits through a product's complete life cycle. Want to learn more about how KatalystDI can support your construction program?
Want to learn more about how KatalystDI can support your construction program?