Often the cost of manufacturing can be reduced substantially if you take into consideration useful design and machining tips.
General Cost Reduction Tips
Use popular materials and check the pricing on different types.
Harder materials (e.g. steel and stainless steel) are usually more expensive than softer materials (e.g. aluminum, plastic, etc.).
Use 2D parts made from sheet material instead of 3D parts made from block material. Stack 2D parts or bend to make 3D shapes.
Instead of machining text use silk screening or labeling.
Make parts multi-functional to reduce part types.
Increase quantity to reduce cost per part.
Use the loosest applicable tolerance.
Use common and simple finishes. Avoid multiple finishes. Use a material that does not require an extra finish process.
Create multiple parts as one object and specify to saw them apart as a secondary process. Note: dimension changes may need to be changed to account for kerf width.
Convert single complex parts into multiple simpler parts that are fit together. For example, to create a large disk with a thin rod protruding from the center you can use piece or design the disk and rod separately. To do it in one piece requires starting with a large block of material and can use ten times as much material compared to making the rod and disk separately.
Tap holes no deeper than three times the diameter when the hole and bolt are the same material (deeper usually adds no strength and can substantially increase cost).
Geometry Cost Reduction Tips
Make shapes simpler or smaller.
Avoid fine details in shapes.
Avoid sharp inside and outside corners.
Increase the radius of inside and outside corners.
Design shapes that don’t waste material. For example, a large U shaped part might be more efficient in three separate sections to avoid wasting the material in the center.
For 3D parts minimize the number of different hole diameters.
Avoid shapes with long protrusions, thin shapes, shapes with lots of material removed, etc.
Avoid the need for complex work-holding. Rectangular parts are the most practical. Round parts requiring milling are a little more difficult. Shapes with complex outer shapes are the most time consuming to setup for holding.
Make narrow slots and channels wider – narrow areas require small cutting tools which work slowly.
Avoid adding explicit chamfers or rounding to edges in a CAD design as edges are normally broken by more economical methods.
Inside deep pockets, for any protrusions close to walls (e.g mounting posts) join the protrusion to the wall so it’s not a separate “island”.
Cost Reduction Tips Specific to 2D Parts
Submit 2D parts with same thicknesses together to lower the setup cost. The max sheet size for 2D parts submitted together is 47.5″ x 22.5″. Minimum distance between the parts must be at least 0.150″ apart.
Reduce sheet thickness.
For parts cut from sheet material, get several different part shapes out of the same sheet.
For holes that are close to an outside or inside edge, some processes will be more efficient by merging the hole with the edge into one contour, so as to reduce the number of times the material must be pierced.
Cost Reduction Tips for Sheet Metal Bends
Sometimes complex bends are more economical and easier to fabricate if you design two simpler parts that bolt together.
Create bends by making slots that decrease strength at the bend location and then bend the parts manually after delivery. (Simply remove the bend lines and in place of each bend line draw a few thin rectangles. To avoid fracturing upon bending the width of the rectangles should be at least 2 times the sheet thickness for 5052 alum, steel, etc. Not recommended for 6061 aluminum.)
Design bent parts to pack efficiently. For example, in designing a large box consider making the sides of the box separate with bolted flanges. Packing efficiency is more important with larger parts. Parts with one bend generally pack much better than parts with two bends. Bends with angles greater than 90 may pack better than those with 90-degree bends.