News

News

Industry News |Metal injection molding vs. machining: When MIM is best

Date: 2019-08-15
Views: 151

Industry News |Metal injection molding vs. machining: When MIM is best

Typical MIM parts used in disposable surgical instruments and assembled in a clean room. (Image from Micro)


Metal injection molding (MIM) works well for high-volume production of small, complex medical device parts of consistent quality.


Demand for small, lightweight, high-strength, complex-shaped components is growing across industries today, from automotive, consumer electronics, aerospace and defense to orthodontics and medical devices.

Traditional machining and injection molding each has its pros and cons in producing components for medical devices, especially where parts may be smaller and require more maneuverability. Metal injection molding (MIM) is a hybrid technology that integrates the shaping capability of plastic injection molding and the materials flexibility of conventional powder metallurgy. Material selection, part size, volume and tolerance are all instrumental factors in the decision-making process.

Materials

MIM is a process like plastic injection molding but with metal feedstock. Powdered metal feedstock is processed at high temperature and pressure to effectively and efficiently produce small, precision, high-performing parts in large quantities. This proven technology yields high-quality mechanical properties and excellent strength, ductility, and magnetic response. It’s ideal for creating components with more sophisticated shapes and small, highly precise parts with unique geometries for surgical instruments, artificial joints and pacemakers.

Process overview

When using injection molding, it’s important to remember not all feedstocks and processes are equivalent. For optimal mechanical properties, high density and small dimensional variation, it’s critical to obtain consistent shrinkage and diffusion of organic binders and surfactants from the metal matrix. Poor diffusion increases the voids in the metal matrix by trapping gas, and the lower density will dramatically reduce the strength of the part.

Due to the flexibility of MIM technology, it’s possible to customize material compositions according to the specific attributes required by customers. Some of the compositions are stainless steels, low alloy steels, carbon steels, Ni-alloys, tool steels and tungsten alloys.

Part size

MIM is preferred for mass manufacturing of small, intricate geometric components of a variety of materials, as it can achieve 95% to 98% of its theoretical density at a much lower cost than comparable machined components.

Volume

MIM is well-suited to automation in producing large quantities with consistent quality. Machining typically requires longer cycle times and is thus better suited for lower production volumes requiring complex shapes with tighter tolerances. Finishing operations with MIM are quite minimal by comparison so long as the application has less critical tolerances. Although there’s an initial capital investment in creating the MIM mold, this cost can quickly be recovered when amortized over high-volume runs.

Tolerance

Expected tolerances range from +/- 2% to less than 0.4%, depending on feature size. The larger the feature, the larger the tolerance due to the propagation of error in shrinkage. Shrinkage generally ranges from 15% to 18% during sintering. Therefore, the larger the feature, the larger the propagation of error. One other phenomenon that affects expected outcomes is non-isotropic. There will be more shrinkage in the vertical direction because of gravity. The least shrinkage will occur in the longest lengthwise direction due to drag forces between the workpiece and the furnace furniture.

MIM is ideal for producing intricately shaped parts for complex components as well as parts that require assembly. The same is true for high-production of small precision parts with complicated design geometry. The process lends itself to automation in which high volumes and consistent quality are required. MIM technology is also the best viable process for producing miniature parts economically.

Companies that specialize in MIM technology and machining should work alongside engineers to address development early on. Engineers with expertise in both processes can suggest design modifications and provide input to get the best performance out of a product no matter what technique is ultimately used. While you can certainly switch operations midstream, factoring in design considerations upfront can save time and costs.

Via: https://www.medicaldesignandoutsourcing.com/metal-injection-molding-versus-machining-when-mim-is-best/

News / Recommended news More
2019 - 08 - 15
Typical MIM parts used in disposable surgical instruments and assembled in a clean room. (Image from Micro)Metal injection molding (MIM) works well for high-volume production of small, complex medical device parts of consistent quality.Demand for small, lightweight, high-strength, complex-shaped components is growing across industries today, from automotive, consumer electronics, aerospace and def...
2019 - 08 - 08
3D printing requires materials called filaments that are rolled onto spools. Source: Dremel Shop3D printing is a great entry point into manufacturing, especially if you’re looking to print small amounts of intricate designs. Here’s what you need to know about 3D printing to help you decide if it works for your ideas.ProsLow entry cost. You can spend as much money as you want to get into 3D printin...
2019 - 08 - 02
Production of components via powder metallurgy has many potential advantages when compared to producing them via conventional methods, such as machining from billets. Some of these advantages include: 1. Huge potential savings in production by using powder metallurgy which is geared towards mass production 2. The flexibility to produce compositions not possible by other methods e.g....
2019 - 07 - 31
CANBERRA, July 31 (Xinhua) -- Australia's Minister for Industry has said 3D printing, food processing and nanosatellites could be the future focus of Australian manufacturing.Karen Andrews, the minister for industry, science and technology, on Wednesday convened a meeting of business groups, the nation's largest manufacturers and the Commonwealth Scientific and Industrial Research Organisation (CS...
Share:
Uniris Exhibition Shanghai Co., Ltd.
Shanghai Branch 
Tel: 4000 778 909 
E-mail:irisexpo@163.com
Guangzhou Branch
Tel:020-8327 6389
Email:pmchina@unifair.com
PM CHINA Official Website
犀牛云提供企业云服务
Scan the QR code to visit the official website by phone