Custom Gear Manufacturing for Small Powdered Metal Parts

Gears transfer torque and rotational motion to drive, position, or hold machine components. Used in pairs or small groups, gears feature precision teeth that engage briefly as they rotate. Gears facilitate motion in automotive systems, medical devices, and manufacturing equipment, and are often exposed to high temperatures, corrosive materials, and heavy use. Therefore, they require close tolerances and robust materials that withstand harsh conditions without breaking or slipping.

Powder metallurgy is a cost-effective, high-precision manufacturing method for custom gears. At Allied Sinterings, we specialize in custom gear manufacturing for small and miniature applications. Learn more about our process and its advantages.

The Process: From Gear Design to Finishing

Our powder metallurgy process is entirely in-house, and includes these steps:

1. Design

Your gear design drawings are converted into computerized models, which serve as the basis for custom molds and corresponding tooling. Part dimensions, tolerance requirements, and part design intent are assessed for optimal manufacturability.

Our capabilities include outside diameters up to 1.25 in., heights to 1 in., and tolerances of +/-0.001 in.

2. Material Selection

Many powdered metals can be mixed in different proportions to fine-tune the mechanical properties of finished gears. Options include bronze, steel, stainless steel, nickel steels, copper, and tungsten. Our metallurgists can help you achieve goals like wear resistance, strength-to-weight ratio, total cost, and more.

3. Powder Preparation

Elemental, pre-alloyed, or partially-alloyed metal powders are custom blended in the specific ratio that meets your requirements. Lubricating additives may be added depending on the application.

4. Compaction

The prepared powder is placed in molds and compacted under pressure. This locks the particles together and fills the mold completely, leaving no voids to cause weak points. At this stage, the part has sufficient “green strength” to be handled; however, it requires heating to reach its final strength, hardness, and density.

5. Sintering

Next, the part (called a “green compact”) is removed from the mold and heated to just below its melting point in a sintering furnace. Several parts are placed on trays and conveyed through the furnace with an automated timing belt. This ensures each part is exposed to the carefully controlled temperature and atmosphere in the furnace for the prescribed time.

6. Finishing

After sintering, parts are cooled in a controlled atmosphere (“quenched”) to reach material properties. They are then ready for use or further finishing. This may include additional hardening heat treatments (i.e., brazing, annealing), machining, plating, or coating.

Benefits of Our Custom Gear Manufacturing Process

Powder metallurgy and sintering offer advantages for custom gear manufacturing, including:

• Precision. Molding and compaction form each gear precisely, with minimal variation from one piece to the next.
• Material Flexibility. A variety of pure and alloyed, ferrous and non-ferrous metal powders are compatible with this process.
• Mechanical Properties. Powdered metals can be blended in combinations and ratios that enhance desired mechanical properties in the finished parts, such as strength, wear resistance, corrosion resistance, and cost.
• Net Shape Manufacturing. Net-shape and near-net-shape processes use material efficiently during blending and compacting. This reduces waste, as well as time and money for subsequent machining.
• Porosity Control. By precisely controlling compaction and sintering, we can achieve desired porosity levels for high-density or oil-impregnated gears that self-lubricate, and everything in between.
• Cost-Effectiveness. Powder metallurgy is cost-effective because it uses only as much material as is needed with minimal waste. High-precision molds achieve tight tolerances, resulting in lower error rates or additional machining. Batch sintering is also efficient.
• Production at Scale. With 42 high-precision, Dorst compacting presses in several tonnages, and three sintering furnaces, we can meet low- and high-volume orders.

Applications for Custom Gears

We serve several industries that require custom gear designs, including:

• Automotive actuators, differentials, steering assemblies, and gearboxes
• Aerospace engines, control systems, flap stems, and rivets
• Consumer-grade mechanical and electronic products
• Heavy-duty gears for compressors, gearboxes, robotics, and pumps
• Prosthetics and medical devices
• Surgical instruments and tools
• Telecom assemblies

Guaranteed Quality

Allied Sinterings is committed to quality, with continuous production monitoring and in-house tooling maintenance. We use a Red Line gear checker to identify defects, test for hardness and density, and use computerized process controls to avoid human error. We are ISO 9001:2015 certified and ISO 13485 compliant and can meet AGMA quality number requirements. Learn more about our quality standards here.

Trusted Custom Gear Manufacturing From Allied Sinterings

Our team can assist you through all stages of gear design, production, and testing. If you are in the design phase of your custom gear project, we have a great resource for you. Download our “Engineer’s Guide to Design Considerations for Powder Metallurgy” ebook which you can utilize to design your gears more effectively. You can also contact us to discuss your project or to request a quote.