AMT | Comprehensive Guide to Powder Injection Molding Appendices

Date：2025-06-10   Views：1013

Table of Contents

Common Heat Treatments for Sintered PIM Alloys

Tool Costing Calculations

Part Costing Calculations

Quality Plan Framework

Resources for Additional Information

Common Heat Treatments for Sintered PIM Alloys

This appendix lists common heat treatments applied to sintered PIM alloys, each designed to enhance specific properties of the material:

• Anneal: Soften and remove residual strains by heating above die recovery and recrystallization temperatures, followed by slow cooling.

• Carbo-Nitriding: A high-temperature modified carburization treatment in an ammonia-based atmosphere that promotes both carbon and nitrogen diffusion into the component surface for hardening, usually followed by quenching.

• Carburization: Heat the component in contact with a carbon source to provide additional carbon in the surface-connected pores to harden the component.

• Case Harden: Use a packed powder or atmosphere gas to diffuse carbon into the exterior surface of the component to increase surface hardness.

• Draw: Another term for tempering, indicating a shift to lower hardness and higher toughness after quenching.

• Nitro-Carburizing: A low-temperature salt bath or gas treatment intended to nitride the component surface while increasing the carbon level.

• Precipitation Harden: An isothermal hold at a temperature where a second phase forms in the microstructure from a supersaturated solid solution, following solutionization.

• Quenching: Rapid cooling from a solutionization or annealing temperature to freeze interstitial elements and alloying elements into the material, usually followed by tempering.

• Sinter Hardening: Controlled cooling from the sintering temperature to induce desired microstructure transformations or precipitation reactions, reducing the number of steps by eliminating reheating after sintering.

• Solutionization: Heat to a single-phase temperature and allow alloying ingredients to enter into solid solution, possibly followed by a quench.

• Steam Treatment: A heat treatment typically above 500°C in an atmosphere containing steam, used to grow a blue-black Fe3O4 tenacious surface oxide on steels.

• Stress Relief: An annealing treatment designed to remove residual stresses from machining or working without altering the basic microstructure, followed by controlled cooling to avoid new stresses.

• Tempering: A post-quenching heat treatment designed to partially transform or modify the quenched microstructure to improve toughness at the expense of hardness.

• Through Harden: Solutionize and quench an alloy to form a hard phase throughout the component.

Tool Costing Calculations

The University of Rhode Island Design for Manufacturing and Assembly Model provides a calculation framework for tool costing:

Assumptions:

• Standard mold base

• Model is based on toolmaker’s time at equal weighting for all tasks

• Final cost is calculated from total time and hourly rate

• Number of cavities is determined by batch size, machine rate, and cycle time

• No rework or design iterations are included

Mold Base Cost:

• CB = 2 (1000 + 0.45 Ad Dd)

• CB is the cost of manufactured mold base including cooling and ejection parts (units of $)

• Ad is die plate area (units of cm²)

• Dd is combined thickness of die plates (units of cm)

Time to Form Mold Actions:

• ts (side pull) = 65 hours

• ts (internal lifter) = 130 hours

• ty (unscrewing device) = 250 hours

Time to Form Cavity and Core:

• tA = 5 + 2.5Ap + 0.085 Ap²

• tA is machining time associated with cutting the projected area (units of hours)

• Ap is projected area of part perpendicular to the direction of mold opening (units of cm²)

Cumulative Mold Cost:

• CT = CB + tj R

• CT is cumulative mold cost for a multiple cavity mold (units of $)

• tj is total time to fabricate the mold (units of hours)

• R is the toolmaker’s hourly rate for mold fabrication (units of $/hour)

Mold Price:

• Cp = CT (1 + CA) / (1 - P)

• Cp is the price of the mold to the customer (units of $)

• CA are fixed administrative costs (dimensionless)

• P is target profit per job (dimensionless)

Part Costing Calculations

The pricing calculations for PIM part fabrication cost and final sale price are highly subjective. The typical price-to-cost ratio in PIM is 1.5 to 1.6, reflecting a 30 to 40% overhead allocated to each job. The cost model is based on a direct allocation of charges against a project, assuming an abundance of projects so that only the proportion of the facility used for any given production run is allocated to the cost calculation.

Per Piece Costing:

• PCi = CTi / U

• PCi is the cost per piece

• CTi is the operating cost per unit time

• U is the average number of parts produced per hour

Additional Costs:

• Overhead: purchasing, sales, marketing, accounting, management, and other business expenses

• One-time expenses: fixtures, inspection tools, handling devices, and other custom-designed production items

• Profit: targeted at 10% across the PIM industry

Quality Plan Framework

A comprehensive quality plan for PIM producers includes the following constitutive parts:

1. Organizational, Sales, and Administrative Systems: System-wide efforts to manage the structure and organize the total process via an organizational quality policy.

2. Communication, Information, and Documentation Systems: Communication systems, including records and information systems, to keep the organization updated on progress.

3. Indicators: Provide quantitative objectives and report on progress.

4. Personnel: Provide training and orientation to all employees, set up training structure.

5. Product and Process Development and Industrialization: Propagate quality standards at the product and process conceptualization stage.

6. Management of Supplier Quality: Suppliers will provide conforming materials, equipment, and products with identified quality levels, including records of incoming materials.

7. Handling of Nonconformities: Including incoming material problems and complaints from customers, records and statistical profiles will be maintained.

8. Maintenance Plans: Efforts will be sustained to ensure equipment and processes remain in conformity with set standards in a preventative maintenance system.

9. Quality of Measurement: Inspection and measuring devices will be employed to assure proper conformance to set standards.

10. Control Systems for Products, Processes, and Procedures: The system looks to improve procedures to propagate the quality system throughout the organization.

11. Audits: Both internal and external audits will be performed to ensure the process is properly conforming to standards.

Resources for Additional Information

For more detailed information on Powder Injection Molding or to discuss your specific needs, please refer to the following resources:

• Technical papers and articles on PIM processes and applications

• Industry reports and market analyses

• Books and manuals on powder injection molding

• Online courses and training programs

• Conferences and workshops