Materials Overview: How Materials Are Organized

Every material on OpusFab belongs to a manufacturing process. When you upload a STEP file and open the configuration screen (or the Edit drawer in the quote table for multi-part uploads), the material dropdown only shows materials that work with the process selected for that part. Change the process and the material list changes with it.

This is because materials and processes are physically linked. Aluminum bar stock can be milled on a CNC machine but cannot go through an SLA printer, and photopolymer resin only exists as a 3D printing material.

The three material families

Metals are used for CNC machining (milling and turning) and metal 3D printing (DMLS/SLM). This family includes aluminum alloys such as 6061-T6 and 7075-T6, stainless steels, and other engineering metals. Metals give you the best strength, stiffness, temperature resistance, and wear performance, and they hold the tightest tolerances (±0.05mm standard for CNC). See Aluminum 6061 vs 7075 and Stainless Steel Options.

Engineering plastics are machined on CNC equipment from solid stock. Common examples include POM (Delrin), ABS, polycarbonate, nylon, and PEEK. Plastics are lighter than metals, electrically insulating, often self-lubricating, and usually cheaper per part. See Engineering Plastics.

Resins and printing nylons are used by the 3D printing processes. SLA printing uses photopolymer resins such as Standard Resin, which cure layer by layer under UV light. SLS printing uses nylon powders such as PA12, fused by a laser. These materials trade some mechanical performance for geometric freedom. See 3D Printing Resins and Nylons.

Finishes depend on the material

Finish options also filter by material. CNC metals offer finishes like Raw (As-Machined), bead blast, anodizing, powder coating, and PVD. Anodizing only applies to aluminum, and powder coating colors are picked from a Pantone/RAL picker. 3D printed parts default to As Printed. The Surface Finishes Overview covers what each finish does.

How to choose

1. Start from the function. Load-bearing or wear parts point to metal. Cosmetic prototypes can be plastic or resin.
2. Check the environment. Moisture, chemicals, UV exposure, and temperature rule materials in or out.
3. Decide how much precision you need. Tight tolerances favor CNC metals.
4. Compare prices directly. Upload your part and switch materials in the editor to see live unit prices for each option.
5. If you are unsure, 6061-T6 aluminum is the safest default for metal parts. It machines well, resists corrosion, and is the most economical alloy in most cases.

The live list is in the quote editor

The material catalog changes as stock and suppliers change, so this knowledge base does not list every material with prices. The current list, with live pricing for your specific part geometry, is always in the quote editor after you upload. If you use BOM import, the downloadable template also has a key at the top listing the valid material and finish names the importer accepts.

If you need a material that is not listed, you can request a custom quote from the upload screen and the sales team will follow up by email.