Generally speaking, Design for Manufacturability (DfM) — or Design for Manufacturing — is the process of consciously and proactively designing products to optimize all facets of manufacturing.
DfM methodology aligns engineering and production in the design phase, ensuring cost and time efficiencies, superior quality, regulatory compliance, and end-user satisfaction. Problems are identified and addressed early in the product development process, preventing costly issues that could impact manufacturability: raw materials selection, tolerances, and secondary processing.
Among today’s manufacturers, both 3D printing and plastic injection molding are viable options for producing complex plastic parts and components. While originally considered competing technologies, these techniques are now each largely recognized as having unique advantages and can even be used together to help optimize production efficiency.
Each new plastic injection molding project has three inherent goals: performance for the customer; production efficiency for the manufacturer; and, reliability for the end user.
These goals are reasonable. The challenge lies in accomplishing all three within a desired timeframe and budget.
To do so, injection molding plastics engineers turn to Design of Experiments (DOE) to identify flaws during the process design phase that might otherwise derail project success.
When it comes to remaining competitive in the global marketplace, speed matters. Manufacturers want injection molded parts that deliver the most product functionality at the lowest cost — and they want the parts quickly to get to market first and fastest.
Injection molders understand the pressure manufacturers are under. They're also attuned to how injection molding design, engineering, and production expertise can greatly speed up development time.
Custom injection molding is a go-to for OEMs across a range of industries because of design and engineering precision, production repeatability, and cost-effective solutions.
Injection molders understand that consistently delivering defect-free parts and products to these standards is a top priority and a true value-add to their OEM partnerships.
Quality assurance begins in the design phase. Engineers are faced with many decisions, but among the most important are those that impact the end of the injection molding process — what has to happen to ensure the plastic part ejects cleanly?
Geometric dimensioning and tolerancing (GD&T) is a symbolic language that is used on engineering drawings and computer-generated models. It communicates geometric dimensions and allowable tolerances for various parts. Not only is this a useful exercise for product design, it’s also helpful on the manufacturing floor because engineers and operators can quickly see the degree of tolerance that is required for each part.
Polymer science has made tremendous strides over the years, rapidly advancing the ability to compound a variety of resins with fillers and reinforcements that provide a vast amount of structural and chemical integrity.
Shrink rates for injection molded plastic parts vary depending on the materials used andwall thickness. Designing uniform wall thickness offers substantial shrink rate control; on the other hand, non-uniform walls can lead to large pressure drops during filling, significant differences in shrink rates, and internal stresses within the injection molded part that could cause warpage or similar defects.
Surface finish on plastic composites can vary a great deal, depending on the physical and chemical properties of the polymer blend as well as the parameters of the injection molding process.
The first objective for a custom injection molder is working with the customer to determine how important the surface finish is for the appearance and/or performance of the final product. For example, does the product need to be eye-catching or simply functional? Depending on the answer, the material selected and the desired finish will determine the settings for the injection molding process, and any required secondary finishing operations.