There are several cost reduction tips that can help you optimize your design and minimize manufacturing costs. Here are some tips to consider
Material Selection
Choosing the right material is key to reducing costs.
For Example: POM (Derlin) is the easiest plastic to machine, while ABS comes in a close second. PEEK and nylon 6 are common engineering plastics that are more difficult to machine.
The alloy known as C360 brass possesses the greatest level of machinability and can be machined at high speeds. Although aluminum alloys such as 6061 and 7075 can also be machined with ease, they necessitate somewhat lower speeds. In comparison, stainless steel is ten times less machinable than aluminum, requiring at least twice as long to machine. The machinability of various steel grades differs, with 304 stainless steel having a machinability index of 45%, whereas 303 stainless steel, a similarly composed alloy, has an index of 78%, rendering it easier to machine.
Select materials that are readily available, easy to machine, and have lower costs.
Standardize Parts
Design standard parts that can be used across multiple products. This can help reduce manufacturing costs by increasing efficiency and reducing the need for custom parts.
For Example: When possible, use through holes instead of blind holes because they are easier to machine.
Design holes with a diameter that is an increment of 0.1mm for diameters up to 10mm. For those above 10mm, use an increment of 0.5mm.
Use standard off-the-shelf components where possible, rather than custom-made parts. This can help reduce costs and lead times.
Optimize Tolerances
Use the optimal tolerances for your design. Tighter tolerances require more precise machining, which can increase costs.
Only define tighter tolerances when it is absolutely necessary.
Define a single datum (e.g. the cross-section of two edges) as a reference for all dimensions with tolerances.
Simplify the Design
Keep the design as simple as possible. Avoid unnecessary features, complex geometries, and tight tolerances that may increase the machining time and cost.
For example: Remove all text and lettering from your CNC-machined parts.
If text is necessary, choose engraved over embossed lettering.
Design parts with a simple 2.5D geometry that can be manufactured in a single CNC machine setup. If this is not possible, separate the part into multiple geometries that can be assembled later.
Some other design tips to minimize cost
Use a radius in the cavity that is at least one-third the depth of the cavity. The larger the radius, the better. Use the same radius for all internal edges to avoid tool changes. On the cavity floor, use a smaller radius of 0.5-1mm or no radius at all.
For metal parts, design walls thicker than 0.8mm. The thicker the walls, the better. For plastic parts, maintain minimum wall thickness above 1.5mm.
When designing threads, use a maximum length up to three times the hole diameter. For threads in blind holes, add at least half the diameter of the unthreaded length at the bottom of the hole.
