How to Design for Manufacturability

October 2, 2021

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9

min read

How to Design for Manufacturability

We know how challenging it is to build a product and to bring it to market.

It requires the combined efforts of many people from a variety of disciplines: design, engineering, quality, supply chain, manufacturing and more. Those experts use tools and methods like operational standards, manufacturing guidelines, business excellence guidelines, which in turn drive process efficiencies and reduce the pain points along this journey.

Manufacturability is an often overlooked consideration during the design process. But it's more important than ever in these competitive times when speed and efficiency are essential for maintaining profitability.

What is Manufacturability?

Science Direct offers an overview of this comprehensive, mindful attitude toward product engineering with the intent: "to ensure that a design is inherently economic to manufacture". Of course, economic factors have always been a consideration when designing products. Until recently, however, that goal was not always a formal process. How do we define manufacturability and make the ideal an innate part of every design process? Read on for some innovative tips as well as reminders of concepts of which we are aware, but sometimes neglect to consider.

A Comprehensive Manufacturability Plan

Simplicity is something you should work toward in all of your designs, but you need to approach the process from the right perspective. For example, to simplify an assembly process, an engineer wishes to combine two parts using additive-manufacturing method. If the result is a much more expensive part, however, then the gain cost is negative. A structured and holistic process is required in order to perform the right cross-functional balancing. Here’s some points to consider:

Keep it Simple & Minimize:

  • Parts: combine parts by using alternative manufacturing methods. In many cases sheet-metal, molding and additive manufacturing offer great solutions for parts combinations. During the production this will simplify the assembly, and will make the supply chain easier (a flatter bill of materials)
  • Types of materials/finishes: this will affect your supply chain, manufacturing methods and movement of parts to and from finish facilities (painting, other). During production this will simplify the tooling and settings of the assembly line.
  • Assembly steps: The fewer steps, the faster the process and less opportunity for error.
  • Sub-assembly orientations: The preferred method of assembly in many cases, is the vertical-stack, bottom-up, in which parts are stacked one within or on top of the other. Gravity helps in this case. If other assembly directions are required (non vertical), try to keep the movement of parts as simple as possible.

Properly prepared designers should be fully familiar with every inherent property of each material which may be utilized in a design project. The better a designer's overall education regarding every type of design material, the faster, more efficient the design process.

Materials possess properties that may require special consideration when used in the design of certain parts or products. Metals are a good example. Features like conductivity, malleability, weldability, ductility, luster, corrosion resistance, impact the manner in which they may be successfully utilized.

When designing each part, it's necessary to consider whether the choice of metal is appropriate for the stress it will be under, which metals, plastics or other materials must adhere to it, or will come into contact with it in some manner. Also, tools used for assembly and their characteristics are important.  For example, if a punch tool is made of the same grade of steel as the part it's used to perforate, it may stick and create galling, resulting in distortion of the hole and damage to the punch.

Part features

Where possible, use standard, off the shelf, available components. By doing this, you have higher chances of getting the parts within their specs and tolerances and getting them at the lowest prices. Getting components in their specs, is a key contributor to a successful automated assembly.

The vision for each part should include careful consideration concerning the position of each perforation or other special feature. This prevents distortion or damage during the manufacturing process, thus reducing waste of time and materials.

The choice of material type and thickness should support strength, while still being appropriate for the function of the part. Established knowledge of a material's characteristics should be followed when specifying when to bend and when to weld, to minimize tears and distortion. Consider where it will be most feasible to punch holes without error or damage to material. Try not to place holes near a part's edge. The act of punching could distort the part's shape.

These and other features known to those familiar with materials and manufacturing processes must be followed religiously.

Tolerances

The total amount a feature may vary while still supporting structure and function must be determined and supplied to the manufacturer. This eliminates guesswork, rejected parts, resulting in excess cost.

The assembly process

The best designed parts are of little use if they are difficult to assemble into a finished product. Designs should be streamlined and should contain as few parts as possible. The more parts required for an item, the greater the likelihood of error at one stage or another.

Many parts also make for a more difficult assembly process. Fewer parts and incorporation of features, like tabs, that make connecting points obvious, simplifies the job of assembling them, thus preventing errors and saving time. Remember that someone or something has to assemble your product, and consider the following:

  • Adding features like tabs, slots, and chambers will make the assembly self-aligned, and will prevent incorrect assembly of parts. This is most beneficial for manual assembly.
  • Parts need to be handled, lifted, grasped. Parameters like dimensions and weight, surfaces for contact, lift or grip should be considered, otherwise additional tasks may be added to the manufacturing process – like orientation, fabrication of special tools, and organization of parts prior to assembly. Leave free areas for adequate tool clearances.
  • Try to avoid parts adjustments or alignments in the assembly process
  • Assure the visibility of parts and components – this is important for both manual assembly – operators will assemble much better if they can see what they assemble, and vision systems could capture images for machine controls or QA.
  • Avoid tight tolerances – both in parts manufacturing and in the assembly, where tolerances are “stacked-up” and in many cases will prevent the parts from being assembled.

Different design options

Don't just come up with the first design that comes to mind and run with it. Consider various potential features and material options. Determine which will be most cost-effective, not simply which is least expensive. A costlier material that will hold up may represent overall savings when compared to a less sturdy material that will result in rejected parts and waste.

The first design you come up with may work, but the second or third will likely be an improvement. Effort spent to hone the design saves money down the line, during manufacturing and assembly processes.  

Open communication channels between design and manufacturing specialists

Design and production are part of the same process, not mutually exclusive entities. What looks perfect on paper may not always work out in the real world where material properties and other manufacturing process factors come into play.

A consultation by designers with those working in the company shop or contracted manufacturing setting can be invaluable in gaining information necessary for creating the most thorough and realistic design possible - one that will produce perfect parts that combine to create a salable product in the first production run.

Manufacturability is Easier to Achieve When AI Technology is Implemented

Automation assembly brings many values and advantages – it improves quality by the repeatable-predictable characteristic of a machine, reduces tedious labor and potential health risks of employees, and can improve capacities and throughputs.

AI can assist in designing for manufacturability, whether the manufacturing process will be implemented with traditional or automated manufacturing and assembly technology. Designing products with both manual and  automated manufacturing systems in mind can reduce complexity, streamline the entire process and save you money.

Today’s computer vision systems are advanced, flexible and intelligent. They can drive machines by image processing. Hence, the visibility of parts, sub-assemblies and related features are critical factors for automatic assembly, guidance, measurements, and inspection. Adding visual features (fiducials) can help to simplify the computer vision application.

AI/data/software can improve manufacturability and expand the types of products that can be easily built. AI data can augment human judgment by detecting discrepancies and variables humans may overlook in choice of materials or design components. Specially designed AI software can enable visualization of manufacturing and assembly processes, so potential issues may be avoided.   Collaboration between humans and machines makes for the highest level of insight and accuracy.

The latest AI design software, as described in the following excerpt from a Forbes post acts as a magic formula for designing a fully manufacturable product:

For manufacturers, artificial intelligence also comes into play through a new process called generative design. It works this way: Designers or engineers input design goals—along with parameters for materials, manufacturing methods and cost constraints—into generative design software. The software then explores all the possible permutations of a solution, and quickly "generates" design alternatives. Finally, it leverages machine learning to test and learn from each iteration what works and what doesn't.

At Launchpad, we provide AI powered user-friendly assembly simulation and autonomous assembly software. Our products support the formation of informed design processes which contribute to manufacturability. Contact us at hello@launchpad.build for the latest information on our software offerings.

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