10 Handy Cost Reduction Tips for CNC Machining To Consider

Cost reduction tips for CNC machining

CNC manufacturing is a cost-effective method when the client and CNC machining service provider understand and implement cost-reducing strategies. These strategies encompass raw materials, the machining process, tooling, power, and design, among other areas.

This article covers these tips in detail and outlines some mistakes people often make. With these ideas and in partnership with a reputable provider, your next CNC machining project should show cost differences.

How Much Does CNC Machining Cost? – The Factors to Consider

Before focusing on the tips for cost reduction, it is crucial to note that CNC machining costs are not usually standardized. Instead, the manufacturer, end user, or dealer encounters several variables in CNC machining cost calculation: CNC machine type/size, cutting accuracy, machining time, part complexity, and the number of parts. 

Other factors are the type of tooling, production cycles, labor costs, power consumption/cost, raw material cost, level of customization, and lead time. 

CNC Machine Type/Size 

Large CNC machines may handle sizeable workpieces, but they occupy larger spaces, cost more, and usually need more expertise. Smaller CNC machines are more affordable, occupy less space, but have less capacity.

The table below shows the estimated cost of machining per hour for three machine types: 3-axis, 4-axis, and 5-axis CNC. 

Note: These are approximate price ranges, which can vary with supplier, region, and time 

Cutting Precision And Tolerance

CNC machines with higher precision are usually more expensive. Most industrial parts are suitable with tolerances of about ±0.1 mm, but tighter tolerances are sometimes required. Because the machinery for tighter tolerances is advanced and the feed rates are slower, the accompanying machining costs can skyrocket. 

A high-tolerance machining center

Machining Time

To achieve faster machining, the manufacturer must invest in more powerful machinery equipped with advanced cooling systems and spindles.  The higher investment cost pays back in per-part cost, particularly in high-volume manufacturing. 

Part Size And Complexity

Large parts require longer machining times, which increases costs because of aspects such as power consumption and labor requirements. CNC machining parts with deep cavities, profiles, and complex geometries requires advanced multi-axis machines, slower feed rates, and higher expertise. 

Large machined part

Number Of Parts

The number of parts affects the CNC milling cost on a per-part basis. For low-volume manufacturing, the machine setup frequency is highest and the tooling changes most frequently. This makes the cost higher.  

Medium-volume manufacturing has a more stable per-part cost, with the cost spread higher. The cost per part is even lower in high-volume manufacturing. However, the machinery to support this level of manufacturing requires a higher initial investment. 

Type Of Tooling

The tooling cost depends on several factors. Some tools are consumable, while others are reusable. Drills, face mills, and other tools that wear out must be replaced over time. Dies and vises are examples of reusable tools that can last the entire life of the CNC machine, hence have no repeated cost to worry about. 

A machinist’s vise

CNC machining costs can rise significantly where special tooling for custom part geometries is required. 

Production Cycles

The production cycle (the series of steps followed from a raw material to a finished CNC machining part) can differ significantly in projects. Optimization means minimizing these cycles as much as possible, and this translates to lower manufacturing costs. 

Labor Costs 

Contrary to a common misconception, the idea of CNC machining being automated doesn’t mean human intervention is completely absent. Indeed, CNC operators still need to program, set up parts and fixtures, inspect the finished part, and monitor the machining progress. 

CNC machining labor

These services are usually charged per hour, with the most experienced experts earning more – upwards of USD 50 /hour. 

Power Consumption/Cost 

The power requirements of CNC machines are equally costly, so a machinist looking to minimize machining costs must focus on this area. Pumps, servo motors, and several other systems are serious power consumers. A 5-axis CNC machine can use several kW per hour. 

Raw Material Cost 

Raw material is another cost determinant in a CNC machining project. Like in many other cost factors, there is always a compromise depending on the type of raw material used. For instance, plastic may be more affordable than metal, but its load-bearing capacity is much lower. 

Level of Custom CNC Machining Parts

Standard CNC machine parts are largely affordable, but customization can change that. Special surface finishes for CNC machining, overly tiny parts, or extraordinarily large parts require special tools and machinery; hence, they are usually more expensive. Custom CNC-machined parts can cost up to 3 times more than standard parts. 

Custom parts  

Lead Time

When a customer orders a CNC-machined part, there is an agreed lead time with the manufacturer. Shorter lead times often cost more than longer ones. Standard lead times can stretch to two weeks, while rush orders are closed within days. The reason rush orders cost up to 50% more is the need to offer priority scheduling, hasten shipping, and use more shifts.

How to Calculate CNC Machining Cost Per Hour

There is a widely accepted formula for calculating the CNC machining cost per hour. 

CNC Machining Cost = (Material Cost + Setup Cost) + (Machining Time * Hourly Rate) + Finishing Cost

Since this is an estimated figure, you should consider contacting ProleanTech for an accurate, comprehensive quote. 

What Is The Typical CNC Cutting Design Price?

The typical CNC design and cutting price depend on many factors, including part complexity and lead time. Most CNC design and machining providers charge per hour, but some shops also provide a flat fee. Overall, complex, custom CNC machining parts are more expensive to design and machine, mostly because of the CAD/CAM preparation and the time it takes to machine them.

10 Tips For Reducing CNC Machining Cost

Careful CAD design considerations and proper planning can prevent the escalation of CNC machining costs. The following 10 proven tips can help minimize the costs in your next CNC machining project. 

#1: Use Cost-Effective Raw Materials

One fact to note in CNC machining cost calculations is that raw material blanks have varied prices. A smart choice of the most cost-effective and workable material can help reduce CNC machining costs. Consider the following estimated prices for common 150 x 150 x 25 mm blanks, price per kg, and common industries for parts drawn from plastics and metals. 

Note: These estimated prices can vary based on factors such as supplier, specific grade, and market rates. Current quotes can be sourced from reliable direct suppliers. 

Where possible, choose the low-aluminum machining cost and avoid expensive ones, for example, the exorbitantly priced PEEK. 

#2: Reduce Raw Material Wastage

CNC machining waste

Excess raw material that must be discarded is a big cost factor in CNC machining, and so, it should be avoided by all means. There are different ways to minimize material waste, including;

• Using common bar stock sizes for different types of parts
• Using adaptive cutting optimizes the toolpath and adjusts the cutting tool in real-time 
• Making smaller cut widths 

#3: Design Parts For Standard Tooling

CNC machining cost calculations repeatedly show that custom tooling can increase machining costs significantly. Unless it is very necessary, stick to standard tooling, as these are more affordable and readily available. 

Furthermore, such tools are compatible with most CNC machines, hence easier to set up. The most effective way to ensure you use standard tooling is to design the parts with such tools in mind. 

#4: Design For Fewer Setups

The exact effect of the number of setups on CNC machining cost may not be definite, but more setups add cost. The machinist keeps on recalibrating tools, resetting the machine, and designing fixtures.  

#5: Opt For Standard Tolerances

While tight tolerances are sometimes necessary, they can increase CNC machining costs. Tight tolerances go hand-in-hand with enhanced inspection, slower machining speeds, and customized tools. 

Chart of tolerance vs cost

Consider using standard tolerances when possible to avoid these costs, which can also be significant. Opting for standard tolerances instead of tighter ones can reduce the CNC machining costs by even 200%, depending on the material and tolerance change. 

#6: Minimize Secondary Finishes

The cost of anodizing aluminium, engraving, and other secondary operations may be high and add time to the machining process. If these finishes are not necessary, it would be cost-effective to avoid them. 

Secondary finished parts

#7: Batch Similar Parts

In low-volume machining, the concept of batching similar parts may appear far-fetched. However, high-volume machining is more cost-effective if similar parts are produced in batch production. You should avoid producing such parts separately to minimize individual costs such as CNC programming, tooling, and setup. 

Similar parts

#8: Plan Ahead Of Time

The planning aspect of CNC machining has a significant impact on cost if the process needs to be expedited. Rush jobs often disrupt the normal working flow of a CNC machining company and could cause a 50% price increase. 

There are many ways to optimize lead times, the most effective one being to enhance supplier communication. Clear communication ensures raw materials are delivered on time and potential problems are addressed promptly. 

#9: Provide Accurate Drawings

A study related to CNC machining cost calculation indicated that up to 30% of CNC machining costs involve drawing mistakes. If your CNC machining drawings have many significant errors, you can expect it to take time to correct them. 

CNC machining drawing

A good provider critically checks all drawings to flag out and remove all design errors and suggests fixing them. The revisions can take time and lead to higher CNC machining costs. 

#10: Work With A Reliable CNC Machining Provider

Working with a reliable CNC machining provider like ProleanTech comes with cost-saving benefits such as;

• Technical expertise that ensures the highest level of design optimization
• Established supplier networks with discounts
• Reduce administration overheads
• Consistent CNC machining quality standards
• Better pricing structures that come with repeat business

The Common Mistakes to Avoid When Cutting Machining Costs

All the above cost reduction tips are very helpful, but they should be applied carefully to avoid common mistakes, such as tight tolerances, poor material choice, overlooking Design for Manufacturability (DFM), and avoiding the cost of prototyping parts. 

These mistakes are summarized in the table below: 

Get more related information from this Design Guide. 

Conclusion 

Balancing the requirement for high-quality CNC-machined parts with the cost-efficiency of the machining process is a constant headache businesses face. There is no two ways about it; they should adhere to established cost-cutting measures. We have discussed the main ones here, which range from choosing the best CNC machining materials to working with reputable CNC machining service providers. 

If you have any questions about CNC machining cost calculation and how to apply appropriate measures in your project, or want to know how our CNC machining services align, contact us now.