Wall thickness is one of the important factors to injection moldings. Non-uniform thickness is the main reason to cause sink marks. In this PDF you will have a general idea of wall thickness based on materials:
In the world of plastics, Design for Manufacturing (DFM) is the combination of art, science and technologies necessary for designing a plastic part or product prior to tooling and production that will meet customer quality and cost expectations. The goal of DFM is to deliver greater levels of customer satisfaction, lower production costs and greater profits.
Injection Molding Part Design For Dummies Pdf Download
On this page, Rosti explores DFM to help our customers and prospects understand its role during the design validation process, prior to tooling kick off. You can download this entire page as a PDF here, read through the entirety of our insights and observations by scrolling down this page, or click on any of the links above to take you to a topic of interest.
Design for Manufacturing (DFM) involves designing a product that optimizes manufacturing efficiencies for the equipment and/or process used in its production in order to realize the lowest possible unit costs at the highest possible quality. The most important reason for integrating DFM into manufacturing a plastic injection molded product is that 70% of its manufacturing costs can be determined by design decisions.
DFM requires choosing the right manufacturing process for a part or product; investments in different technologies, using state of the art design principles (discussed below), and selecting the right materials with the right properties to deliver the consistency and quality demanded by your customers and prospects.
Beyond just estimating manufacturing costs, your injection molder should be using DFM principles to reduce the costs of components, reduce the costs of assembly, reduce the costs of supporting production, and to identify the impact of DFM decisions on other factors throughout the entire design and production process.
Another reason for selecting a molder that uses DFM principles is the increasing complexity of plastic injection molded parts. Consideration of tolerance, draft angles, undercuts, and more, need to happen in the design stage in order to achieve the quality/cost requirements of customers.
Shrinkage is the contraction of the molded part as it cools after injection. All materials have different shrink rates depending on resin family (amorphous vs. crystalline materials), mold design, and processing conditions. Resin may also shrink differently depending on direction of flow. As a general rule of thumb, a 10% change in mold temperature can result in a 5% change in original shrinkage. In addition, injection pressure has a direct effect on shrinkage rates. The higher the injection pressure, the lower the shrinkage rate. View typical mold shrink rates here.
In addition to main areas of a part, uniform wall thickness is a crucial design element when it comes to edges and corners. Adding generous radii to rounded corners will provide many advantages to the design of a plastic part including less stress concentration and a greater ability for the material to flow. Parts with ample radii also tend to be more economical and easier to produce, with greater strength and appearance.
Many designers think that by making the walls of a part thicker, the strength of the part will increase. When in reality, making walls too thick can result in warpage, sinking, and other defects. The advantage of using ribs is that they increase the strength of a part without increasing the thickness of its walls. With less material required, ribs can be a cost-effective solution for added strength. For increased stiffness, increase the number of ribs rather than increasing height and space a minimum of two times the nominal wall thickness apart from one another.
Surface finish options for plastic injection molded parts vary depending on part design and the chemical make-up of the material used. Finishing options should be discussed early in the design process as the material chosen may have a significant impact on the type of finish implemented. In the case where a gloss finish is used, material selection may be especially important. When considering additive compounds to achieve a desired surface finish and enhance the quality of a part, working with an injection molder that is aligned with knowledgeable material science professionals is essential.
Design for assembly (DFA) is a process by which products are designed with ease of assembly in mind with the ultimate goal of reducing assembly time and costs. The reduction of the number of parts in an assembly s usually where the major cost benefits of DFA occurs.
Material selection is a critical part of the DFM path to high quality/low cost/fast production plastic injection molded parts and products. The sheer number of types of plastics and their associated properties makes discussions between material providers, injection molders and product manufacturers critically important, as addressing specific needs early in the design process is key to avoiding costly changes later.
In recent years, plastic injection molders have turned to the principles and technologies associated with scientific molding. The goal of scientific molding is to (1) save developmental costs and time by eliminating trial and error in the design process, (2) create dependable, defect-free tooling that eliminates costly mold rework, improves part quality, and accelerates time to market, and (3) create a repeatable and easily auditable manufacturing process.
The technology of scientific molding is delivered through simulation software like SOLIDWORKS Plastics Premium software (mold flow simulation) and executed through robotics and process control systems like RJG eDart that produces consistent, high quality parts and products including predictive insight, process validation and complete process documentation. To complete the technology picture, plastic injection molders should be using state of the art Enterprise Resource Planning (ERP) software like IQMS that provides complete, centralized financial and operational management
Using and integrating technologies supporting the plastic injection molding DFM process is challenging. It involves communication and collaboration between molder, OEM and customer, across many different disciplines.
Over the years, best practices for tooling and part manufacturing have changed substantially. While production checklists are still critical components of the process, the work that happens earlier in the development cycle is what creates real efficiencies in regard to time and budget. When a tool-maker / injection molder is involved early in the development cycle, customer objectives are understood and unexpected surprises are avoided.
Are you looking for an injection molding that can provide expert consultation from design to production completion? Connect with Rosti's knowledgeable team members that focus on all areas of design for manufacturability, development, and production.
Most traditional manufacturing processes like injection molding, thermoforming, or casting require custom tooling to create end-use parts. However, tooling comes with high upfront costs and weeks or months-long lead times from service providers, slowing down product development and extending the time it takes to get a product to market.
Incorporating in-house rapid tooling such as 3D printed molds, patterns, and dies into the product development process empowers businesses to validate the design and material choice before transitioning to mass production and provides an affordable means to produce custom or limited series of end-use parts.
Incorporating rapid tooling into the product development process enables manufacturers to validate design and material choices prior to transitioning to mass production to accelerate product development, iterate quickly, and bring better products to market. Rapid tooling empowers engineers to use the actual production-grade materials to evaluate how the parts will perform in real-world applications and produce limited volumes of products for beta and validation testing. Rapid tooling can also help troubleshoot the manufacturing process before investing in expensive production tooling.
Rapid prototyping is the group of techniques used to quickly fabricate a scale model of a physical part or assembly using three-dimensional computer-aided design (CAD) data. Because these parts or assemblies are usually constructed using additive fabrication techniques as opposed to traditional subtractive methods, the phrase has become synonymous with additive manufacturing and 3D printing.
Hard tooling is a synonym for metal tooling, most often in the context of injection molding. Hard tooling can be produced with rapid tooling methods, mostly out of aluminum. Hard tooling is durable and can handle large production volumes, but incurs substantially higher costs than soft tooling or most rapid tooling methods, making it more suited to mass production.
In this webinar, Juliette Combe from Formlabs will discuss the possibilities of in-house rapid tooling with 3D printing, while Max Rodriguez and Thangthip Tekanil from PepsiCo will explain how they have internalized this process in their rapid prototyping department for bottle and nozzle design, among other things.
Injection molding is one of the most popular manufacturing processes for thermoplastic, silicone, or rubber parts. Due to the excessively high costs of traditional metal tooling, it is also the process that can benefit most from rapid tooling.
With affordable desktop 3D printers and temperature-resistant 3D printing materials, it is possible to create 3D printed injection molds in-house to produce functional prototypes and small, functional parts in production plastics.
For low-volume production (approximately 10-1000 parts), 3D printed injection molds save time and money compared to expensive metal molds. They also enable a more agile manufacturing and product development approach, allowing engineers and designers to create functional prototypes or low-volume end-use parts to validate material choice and continue to iterate on their designs with low lead times and cost before investing in hard tooling. 2ff7e9595c
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