.cta-box a { color: white !important; } .cta-box a:visited { color: white !important; }
Posted April 1, 2021

How To Calculate CNC Machining Costs: What You Need To Know

CNC machining for low-cost precision part manufacturing

Calculating the cost for CNC machining involves various cost factors, including labor, machine, complexity, materials, and many others. CNC machining provides one of the most cost-effective options for on-demand production, but customers still require accurate price estimates before a new project begins. Some machine shops simplify this process with instant online quotes. This article will break down the factors that go into calculating CNC machining costs and offer some tips for optimizing budgets.

CNC Machining and Related Cost Factors 

To optimize costs on a design, one should understand the various factors that impact prices. Sometimes reconsidering a material or surface finish could significantly reduce the bottom line. Machine shops consider the following key factors when determining the cost for a project: 

Machining 

Machine shops use machines such as mills and lathes for part fabrication. 3-axis and 5-axis milling and turning machines provide the flexibility to design parts with complex geometries and tight tolerances. Machining costs depend on the type of machine and the number of hours it will run, typically referred to as machine time. Shops set an hourly rate for running different types of machines. 

The hourly cost for a 3-axis milling machine is generally around $40, while for CNC lathes, the cost can be about $35 per hour. 5-axis machines may charge anywhere between $75 to $120 per hour or higher. These costs are independent of human labor. Each machine offers an advantage that depends on the geometric complexity of a part. Before sending a design to a machine shop, one should optimize the design as much as possible. 

Part Features

A part’s features refer to the geometry and complexity in design. For parts with complex features, more programming time, run time, and setup time becomes necessary. Complex parts may also demand specialized tools, multiple setups and machines to fabricate, increasing the final product’s cost. It is beneficial to simplify designs wherever possible to reduce the cost per part. Simplify the design by eliminating unnecessary features. In some cases, it might be more cost-effective to split a design into multiple parts and then assemble.

Material 

A material’s cost and machinability will be a major factor in determining the cost. Materials include aluminum, stainless steel, plastics, and many others. The general cost (as of March 2021) of commonly used CNC material per block of 6” x 6” X 1” dimension are:

 

Metals

Aluminum 6061

$25

Aluminum 7075

$80

Stainless steel 304

$90

Plastics

ABS (Acrylonitrile butadiene styrene)

$17

POM (Polyoxymethylene/ Delrin)

$27

Nylon 6

$30

 

Subtractive manufacturing deals with sequentially removing material, so the amount removed correlates with the machining time and price. Careful selection of material size can make a significant difference in the calculation of CNC machining costs. If one requires a rapid prototype, aluminum and plastic are faster and more affordable to produce. A general rule of thumb is to select the least expensive material without sacrificing form, fit, or function.

Labor 

CNC machines require almost no human intervention once set up. A machinist, engineer, or programmer must perform specific steps. Those include:

  • Programming: A programmer converts a CAD file into a CAM file for the CNC machine to process. Some AutoCAM technology automatically programs toolpaths, greatly reducing the reliance on humans for this step in manufacturing.
  • Setup: A machinist will set up the machine/s for production. Someone always has to cut the billet, set it up in the workholding and load the tools into the tool changer. The cost depends upon the quantity and complexity of parts produced.
  • Quality control: Quality procedures differ from one shop to the next. Typically a shop will have a quality team and training that varies depending on roles.
  • Post-processing: Part-assembly, cleaning, support removal, and surface finishes typically require manual intervention. 

Labor costs in CNC machining are highest at start-up, but companies can offset those initial investments at higher-volume production. Additionally, recent developments in online quoting systems, tooling, machine design, and CAM software have optimized production cycles and lowered labor costs.

Finishes

Surface finishes improve the final surface of a part, removing any tool marks or roughness, fulfilling cosmetic purposes, and providing wear resistance. Machine shops offer a wide range of surface finishes for different materials. Surface finishes affect part tolerances and range from simple “as-machined” to more expensive anodizing or bead blasting. The surface finish depends on a part’s application. A qualified machine shop can help determine the most prudent option.   

How To Calculate CNC Machining Costs: Auto Quote System

Plethora’s online quoting system makes cost calculation for part manufacturing fast and convenient. Customers can:

  • Upload the CAD design, including parts’ dimensions and tolerances.
  • Input part details, including material, quantities, and finishes required.

Proprietary auto DFM software analyzes part geometry, calculates rough material size, current material costs, and optimal tooling. Additionally, it considers how many setups the part may require based on how many sides have features and estimates the total runtime. Online quote systems allow fast retrieval of manufacturing costs and reduce the chances of error and unexpected expenses during fabrication.

CNC Machining and Cost Calculation

For high or low-volume parts production, understanding the machines, labor requirement, part complexity, finishes, and production time is essential. However, the process of machining cost estimation is prone to errors and requires careful assessment. With Plethora’s Auto Quote system, you can get all the tools and cost information immediately. The selection of optimal tools and materials will allow you to increase productivity while saving time and costs.

To learn more on how to calculate the CNC machining costs, contact the experts at Plethora. Give us a call at 415-726-2256, or to generate an instant online quote, upload your design files to Quote My Part, and start your project today. 

Quote My Part

the-plethora-team

The Plethora Team

The Plethora team is your go-to CNC manufacturer for hardware done right the first time. We have the tools and experience needed to create high quality custom parts quickly and with precision, whether you need a prototype or production run.

Topics: Design, Manufacturing, finishing, CNC machining, Quality, Prototyping

Comments