Optimize CNC Design

Tips for Optimizing CNC Design
Jack Lie CNC machining expert

Specialize in CNC Milling, CNC Turning, 3D Printing, Urethane Casting, and Sheet Metal Fabrication Services.

In order to guarantee prototypes and production parts manufacturing process fast and cost-effective, we need to balance the capabilities of CNC machining and optimized part designs. There are several critical considerations in CNC designing process for our milling and turning process, which will accelerate production cycle time and reduce final costs.

Optimize CNC Design Image
Optimize CNC Design

Six Main Elements Affect CNC Design

To optimize your design for machining process, there are 6 elements you should focus on:

  1. Hole depth and diameter
  2. Wall height and feature width
  3. Thread size and types
  4. Live-tool lathes
  5. Text on parts
  6. Multi-axis milling

Hole Features

As anyone in machining centers will be familiar with drill bit appearance and its functions. For most part, we will interpolate holes with endmills or drills. In this case, the endmills machining method will provide great flexibility in hole size with same tool, and better surface finish than drilled options. Endmill machining also encourages us apply same tool for slots and pockets machining, reduce cycle time and final production cost. While the only downside is that endmills have challenges to mill deep hole with more than 6 diameter. We need to machine form both parts side in reason of endmill limited length.


Drilling and Threading always work hand in hand, most machining centers use taps to cut internal threads. Taps looks like a screw with teeth, and thread into a previous drill hole. Now, we apply  an more advanced approach for thread manufacturing, a new tool called thread mill is used to interpolate the thread profile. This can create an accurate thread, a single milling tool can cut any size threads with same pitch, save production and setup time. In reason of this, UNC and UNF threads up to 12.5mm and metric from M2 to M12 are possible to produced with a single toolset.


In most cases, customers want to add parts number, description, logo on parts surface, Runsom is capable of machining any text required with our restrictions. The space between individual characters and the character width should be at least 0.5mm. We recommend recessed text rather than raised text in reason of less operation time. The most suitable text font are 20 point with Arial, Verdana or similar Sans-serif fonts.

Tall Wall

As our toolsets are consist of high carbide cutting tools, this super rigid metal has maximum tool life and productivity with minimal deflection. However, even the strongest tools will deflect, especially for high intensity steel machining. In reason of this, wall height and feature size are limited strictly by the individual part geometry and applied toolset. Such as in Runsom, our minimum feature thickness is 0.5mm, and the maximum depth is 50mm, but it doesn’t mean we can produce a ribbed heatsink with these dimensions in you design.

Live Tool in Lathes

We also provide live-tool CNC turning, these toolsets are similar to our machining centers. This can encourage us to machine off-center holes, slots, flats, and other parallel or perpendicular features, and follow the design rules as our machining centers. The difference is the raw materials shape, turned parts start our as round stock, while milled parts apply square or rectangular blocks instead.

There are some obvious parts for lathe turning process, such as piston in spool valve or hydraulic fitting. All these component are cylindrical symmetry, and consist with complex external geometry and challenge internal features. CNC lathes can produce these parts in the most cost-effective way. However, the rectangular valve body with large milled surface, internal pockets and intersection bores will never be rotated by lathe machines, no matter the live-tools capability in lathe machine.

This is the main reason why we add end milling tools to our CNC turning centers, in order to produce better surface finishes on cylindrical features at a typical lower price. This lathes also increase our efficiency of special parts manufacturing, which parts need edge skating of milling process. Especially for low-volume production.

As turning parts offer several advantages over milling, such as long length to diameter ratios on piston, which is more difficult to produce by milling process, but easy by lathe. Once you have design concept for your next project, we can deliver the best turning prototype for you geometry requirement.

3-axis and 5-axis Machining

In Runsom, with 3-axis machining, all workpieces are gripped form raw material blank bottom area, and all features are cut form 6 orthogonal sides. For large parts more than 250mm, we can only machine the top and bottom area. With 5-axis machining, feature form any non-orthogonal sides is possible. The toolset in these 2 case are identical, the only difference is the raw material.