Careful planning is crucial for carrying out any kind of operation, whether dealing with the military or industrial machining. We can’t deploy machinists (troops) without knowing which operation will have the best effect (fewest casualties).
While it isn’t a life-or-death situation like war, deciding what goes into your CNC milling project can save greatly on both time and costs. But new entrepreneurs often make the mistake of skipping this crucial first step.
Why is planning so important? Put simply, CNC milling is an expensive process. Doing and redoing any operation can seriously disrupt your budget. After all, devising a war plan after you’ve already lost all your troops is futile.
Prototyping is good, but meticulously planned prototyping is, arguably, the best.
Identifying the design and development factors leading to high CNC costs is key. Equipped with the right insights, entrepreneurs can then adjust these factors, minimize their use, and eliminate any production-heavy aspects in the early stages of production. Some of the most common cost-increasing factors include overly specific tolerances, expensive materials, and elaborate surface finishes.
Below are some expert tips for saving on both time and costs during your next CNC milling project.
1.Select Raw Materials Wisely
Materials influence cost both as raw materials and in terms of how machinable they are. A raw material’s cost can be low, yet if it’s difficult to machine this can end up costing more than a slightly more expensive raw material that’s easier to machine. In general, softer materials are easier to cut so they take less machine time, and can be cut using less expensive tools. Hazardous materials that require additional safety precautions can also add to production costs.
The cost of raw materials is a major factor in any CNC machining project. While these costs cannot be eliminated, optimization is possible.
For example, a better CAD file design can lead to better utilization of materials, reducing material costs. Also, using tighter tolerances leads to lower rejections, eliminates considerable waste, and reduces material costs.
Besides the amount, the type of raw material is also an important factor that affects raw material costs. For example, plastics are cheaper than metals.
For CNC machining, the material cost is compared based on standard sheet sizes of 6″ x 6″ x 1″. Here is a comparison of some common materials per standard size:
- Stainless Steel 304: $90
- Aluminum 7075: $80
- Aluminum 6061: $25
- Nylon 6: $30
- Delrin: $27
- ABS: $17
One of the simplest ways to stay within budget, assuming it meets your requirement, is by switching to a more machine-friendly or less expensive material. Our material selection includes a range of metals and plastics, each with its own engineering attributes, aesthetics, machining considerations, and material cost. Here are some key material considerations:
- 17-4 PH stainless steel is difficult to cut. If high strength and corrosion resistance isn’t critical, try 316L or 304 instead.
- Copper is a great electrical conductor, but it’s far more expensive than aluminium. While aluminium is roughly 60 percent of the electrical conductivity of copper, the weight and cost savings may drive you to reconsider aluminium.
- If hardness is a concern, 4140 might be your first choice, but 1018 is very low cost and takes an admirable case hardening.
- One sure way to make a machinist smile is to give him or her an order for some brass parts, a soft metal that’s easy to mill and might just have the mechanical, chemical, or conductive properties needed for your application.
- On the plastics side, we have nearly three dozen to choose from. All of them are relatively easy to cut, a factor that often—but not always—equates to lower cost parts. Some plastics offer superior wear, corrosion, or chemical resistance, others perform well under heat or flame, while still others offer excellent strength, impact, or electrical properties. Typically, the softer the material, the more risk for dimensional stability and stringing when milling.
Not sure which material to consider? Please feel free to check out the complete material list or call one of our applications engineers for advice.
2.Reduce the Number of Setups — and Setup Time
You’ve listed your raw materials and selected the process. You already know what the end product will look like. Now come the intermediate steps: operations and setups.
Each machined part involves one or many operations. Every operation necessitates a series of setups. There is machine setup, of course. But there is also CAM programming (which will be different for cutting, milling, and drilling processes), part fixturing (if required), material setup, and more.
You can skip all the mess — and expenses — by cutting down on the number of setups. Most parts can be wrapped up in six setups or less. Try to get this number down to two necessary steps — or one, if possible.
Fewer setups will reduce setup time by half or more. And in this way, you’ll be able to machine CNC milled parts better and faster.
- Machining time: This is usually the primary cost driver when it comes to CNC machining. As a rule of thumb, the longer a part takes to machine, the more it will cost.
The finish of your CNC machined part helps protect it against harsh environments and often improves its appearance. Unfortunately, it also drives the cost up. Taking it another step further and asking for multiple finishes on one part increases the cost even more.
If you want to save money, consider choosing the as-machined finish for the entire piece. Only ask for multiple finishes when you need them.
This applies to surface roughness or texture, and appearance-altering finishes like chem film, (sometimes called chromate,) or anodizing.
Mixing and matching adds a lot of cost. For example, requesting a mixture of anodized and chem film finishes on a part adds several processing steps. The same applies when specifying a smooth finish in one area and a bead blast finish elsewhere.
In terms of surface smoothness, it is best to either leave it open or request a uniform finish. If in doubt, it helps to explain the part’s function to your project manager.
3.Split Up Complex Parts
If you have a complex part — such as intricate geometries, rotating or repositioning required — machining your part is likely going to involve a custom fixture, manual rotation, repositioning or a multi-axis CNC system. All of these come at a cost.
If you aren’t able to make your part any less complex, you still may be able to find a way to reduce CNC machining costs by splitting the part into two or more separately machined parts that can be assembled to create the part you need. By breaking the part down into two or more geometries that can be machined in a single setup, you’re likely to find a cost reduction.
A part’s dimensions, including size and complexity, have a big effect on cost. Larger parts consume more material. Complex, highly detailed parts require multiple processes and may also require multiple machines, adding to programming, fixturing, and setup costs. Some complex parts, such as those needing operations on multiple faces, may be less expensive to produce if designed as separate components joined together after machining.
High design complexity leads to high design costs and higher CNC machining costs. In most cases, a complex design will require CNC milling machines with more axes, which can double or triple the total cost.
Most complex designs can be divided into two or several simpler designs and then milled by 3-axis CNC machines. Assembly of these simple designs can create a complex product. By doing this, the CNC machining cost can be reduced significantly.
The same principle applies to overall part geometry as well. Don’t attempt to make parts do more than they should. Maximizing material usage may create work holding or machining problems, in turn increasing costs. If the design gets too complex, consider breaking it into multiple components and using fasteners to assemble them. No one likes assembly costs, or the complexity that goes with multiple pieces, but it might be the best approach for difficult-to-machine parts if speed is one of your requirements. Sculptured surfaces, cavernous slots (think heatsinks), super deep holes (hydraulic manifolds), and threads—these are some of the common machining cost drivers that can chip away at your project budget.
4.Specify Tolerances Only for Critical Features
Specifications are crucial for precision CNC machining. Entrepreneurs usually define what they want and how they want it. But part design — specifically, tighter tolerances — has a huge impact on production costs.
We recommend that you maintain standard tolerances for general features. You may specify tolerances for certain critical features and functions if absolutely necessary.
Similarly, maintain a specific dimension for holes for milling. Smaller (and deeper) holes take up a significant amount of machining time and may trigger tool breaks.
When your part design includes a tight tolerance, it drives up the cost because it increases the machining time and adds a manual inspection. Unfortunately, tight tolerances are particularly tough to achieve on the internal surfaces of your part, as machining holes and other cavities can develop burrs on the edges. These burrs require an additional step beyond the manual inspection — deburring. Deburring is a manual and time-consuming process that also drives up the cost of CNC machining.
If a specific tolerance isn’t defined by the design, the standard tolerance of ± 0.010 thousandths or better is used. This standard tolerance works well for many features, so you should reconsider any tight tolerances you have and only specify tight tolerance when it’s necessary. If you have advanced design knowledge, you can further reduce the cost of CNC machining, as the tolerances that come with them are usually looser.
One final note regarding tolerances — the numbers that represent your dimensions are critical, as they specify the level of accuracy you require for your part. In CNC machining, that level of accuracy translates to what tool will be used to machine it. The more decimal places you include, the more intricate the tool, and the higher the cost. Make sure you eliminate all unnecessary decimal points from your design.
Defining tight tolerances increases the cost of machining a feature, so it should only be done when absolutely necessary. If a specific tolerance is not defined on the technical drawing, the parts are machined using the standard tolerance (± 0.125mm or better). This is sufficient for most non-critical features.
To minimize cost:
- 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.
Pro tip: Use Geometric Dimensioning and Tolerancing (GD&T) in technical drawings to reduce the cost of CNC machining . GD&T includes features such as flatness, straightness, circularity, and true position. It often defines a looser tolerance, although it requires advanced design knowledge to apply effectively.
Not every surface of a design needs tight tolerances, and too many unnecessary ones increase a part’s overall cost. Usually, numerical callouts are only required for the surfaces and features that are absolutely critical to a part’s function, where it interfaces with others. Less important features can be machined using the standard tolerance of +/- 0.127mm (+/- 0.005 in.).
A tighter tolerance results in greater accuracy in the final product. However, a top-quality machine that can cut with precision to tighter tolerances as part of the manufacturing process will cost more. Therefore, requiring tight tolerances increases the CNC machining cost for a project.
Typically, only a few surfaces of a part are critical to its function. The more features with numerical callouts in the design (e.g., radii, hole diameters and chamfers), the more expensive a part becomes to manufacture.
In order to eliminate unnecessary costs, the key is to only assign numerical values to mission critical features and surfaces. Other, less significant features should be controlled by the model (standard tolerance of +/- 0.005″).
Also, try to define a single datum, like the intersection of two sides or the center of a hole, and then dimension everything else from this.
At CNCchinese, our typical tolerance accuracy ranges from 0.005″ – 0.001″, depending on customer specs.
5.Maintain a Standard Radius of 3 mm for Inside Corner
The rule of standard specifications applies to inside corners as well.
Milling small, specific radii for inside corners is expensive, time-consuming, and often requires special setups — especially if you’re operating with very small cutters. This is because CNC machines generally run vertical milling operations on the workpiece.
The ideal inner corner radius for most of the machined parts is 3 mm, or ⅛ inch. You can save on setup time and expenses by following standardized radii for noncritical features.
To ensure your design doesn’t slow down machining tools, let them do what they already do automatically. Tools like milling cutters and end mills automatically leave rounded internal corners, and the wider the corner’s radius the less material the tool must remove, reducing passes. Narrow inside corner radii with length-to-diameter ratios greater than 3:1 need more passes and special small tools, increasing machining time and requiring tool changes. You can also reduce machining time and tool changes by maintaining the same radii for all internal corners.
A CNC machining tool – such as an end mill or milling cutter – will automatically leave rounded inside corners. The wider this radius, the less passes that the tool will need to make to remove material.
By contrast, a narrow inside corner radius requires both a small tool to machine away material and more passes — often at slower speeds to reduce the risk of deflection or tool breakage — resulting in more machining time.
For optimum design, use an inside corner radius that has a L:D ratio (length to diameter) of 3:1 or less. In addition, try to keep internal corner radii the same, if possible. This helps eliminate tool changes, which adds complexity and can increase run time significantly.
6.Add a radius in internal vertical edges
All CNC milling tools have a cylindrical shape and create a radius when cutting the edge of a pocket. A corner radius can be reduced by using a tool with a smaller diameter. This requires multiple passes at lower speed because smaller tools cannot remove material as quickly as larger tools in just one pass. This increases machining time and cost.
To minimize cost:
- Add a radius of at least one third of the depth of the cavity—the larger, the better.
- Use the same radius for all internal edges to eliminate the need for tool changes.
- On the floor of the cavity, use a smaller radius (.5 or 1mm) or no radius at all.
Good to know: Ideally, the corner radius should be slightly larger than the radius of the tool used to machine the cavity. This reduces the loads on the tool and thus manufacturing cost. For example, if your design has a cavity that is 12mm in depth, add a 5mm (or larger) radius at the corners. This allows a tool with an 8mm diameter to cut at a faster speed.
Pro tip: If you need internal edges with sharp corners (e.g. when a part with a rectangular shape needs to fit in the cavity), instead of reducing the internal edge’s radius, use a shape with undercuts like those shown in the image below.
7.Limit the depth of cavities
Machining deep cavities affects the cost of CNC parts dramatically because a lot of material must be removed. This is both time-consuming and wasteful.
CNC tools have a limited cutting length. They typically work best when cutting cavities with a depth of up to two to three times their diameter. For example, a milling tool with a 12mm diameter can safely cut cavities up to 25mm in depth. It is possible to cut deeper cavities (up to four times the diameter of the tool or greater), but this drives up cost because special tooling or multi-axis CNC systems are required.
To minimize cost:
- Limit the depth of all cavities to four times their length—that is, the largest dimension on the XY plane.
- Adjust the internal corner radii accordingly. Use the advice in tip number 1 if needed.
8.Increase the thickness of thin walls
Unless weight is a major concern, manufacture thick solid sections because they are more stable and less expensive to machine. To avoid deformation or fractures when machining a thin wall, use multiple passes at low cutting depths. Thin features are also highly prone to vibrations, so machining them accurately is challenging and increases machining time considerably.
To minimize cost:
- For metal parts , design walls thicker than 0.8mm—the thicker, the better.
- For plastic parts , keep the minimum wall thickness above 1.5mm.
Good to know: The minimum wall thickness that can be achieved for metals is 0.5mm. For plastics, it is 1mm. Assess the machinability of such features case by case.
Important: Thin walls are often an issue when placing holes (and threads) very close to a part’s edge. Take this into account when designing for CNC machining.
9.Limit the length of threads
Including threads that are longer than necessary can increase the cost of CNC parts because special tooling may be required. Threads longer than 1.5 times the diameter of the hole do not enhance a connection’s strength.
To minimize cost:
- Design threads with a maximum length of up to three times the hole diameter.
- For threads in blind holes, add at least half of the diameter of the unthreaded length at the bottom of the hole.
10.Avoid Complex Part Geometry
A part’s dimensions, including size and complexity, have a big effect on cost. Larger parts consume more material. Complex, highly detailed parts require multiple processes and may also require multiple machines, adding to programming, fixturing, and setup costs. Some complex parts, such as those needing operations on multiple faces, may be less expensive to produce if designed as separate components joined together after machining.
11.Avoiding Multiple Finishes
A high post-processing finish will require CNC machines to spend a long time on the product to create higher quality edges. This leads to added machine costs, labor costs, and more wear on the tools. Therefore, avoiding multiple product finishes is a good idea.
Many products go through secondary finishing processes that lead to additional completion costs. Using the final CNC milled product as the finished product is a cheaper option.
12.Optimization of Design
CAM blueprints create the basis for the design of the finished products. CAM programming blueprints are then converted to CAD designs, and the program file uploaded to the machine gives instructions on how to cut parts.
Optimizing the design will lead to machines taking the shortest routes and cutting the minimum amount of material required to create the final product. This leads to better utilization of time and raw materials.
Therefore, optimized designs and CAM software lead to reduced raw material costs and shorter machining time. This is especially the case for large production runs. Investing more in the design process planning is recommended to save CNC machining costs in the long run.
High design complexity leads to high design costs and higher CNC machining costs. In most cases, a complex design will require CNC milling machines with more axes, which can double or triple the total cost.
Most complex designs can be divided into two or several simpler designs and then milled by 3-axis CNC machines. Assembly of these simple designs can create a complex product. By doing this, the CNC machining cost can be reduced significantly.
13.Eliminating Sharp Edges
Sharp edges and 90-degree corners are more time-consuming for CNC routers. This is because a CNC router goes to the edge, stops, turns 90 degrees, and then starts over again.
A better way to utilize the time of CNC machines is to use rounded edges and corners. With rounded corners, the machine can create the edge without stopping.
14.Expand Thin Walls
Thin walls take time to machine because they are fragile. Thin walls are machined through multiple passes with low setting depths to avoid any errors or fractures. A common cause of thin walls has to do with the placement of holes and threads near the edge of the part. Place them strategically.
Thick walls are more stable and cost less to machine. As long as the weight isn’t a concern, design metal parts with walls thicker than 0.8 millimeters and plastic parts with walls thicker than 1.5 millimeters.
In most cases, it is a good idea to avoid any need to mill thin walls because they require extra care in the CNC machining process. Thin walls are delicate and can break due to the force or vibration of the CNC lathe.
Therefore, to mill thin walls, a CNC machine must cut slowly, leading to added time and cost. Even with extreme care, there is a possibility that the thin wall may break, leading to a higher rejection rate.
Replacing a thin wall with a thicker one may increase the material cost fractionally, but doing so will significantly reduce the CNC machining costs.
Parts with overly thin walls — often defined as thinner than 0.794mm (1/32 in.) — are not a good choice for CNC machining. Walls that thin can cause distortion, making it difficult to maintain tolerances. They can also cause chatter, slowing down machine speeds. Both lead to additional costs in machine and operator time. Other manufacturing methods, such as sheet metal fabrication, may be more cost-effective for constructing walls thinner than this minimum.
15.Optimize Tapped Holes
The two factors that affect cost when it comes to tapped holes are depth and tap size. As we mentioned, increasing the length of a thread beyond a point doesn’t make the part any stronger. Going deeper than three times the hole diameter comes with an increased risk of breaking the tap and additional time — both of which can increase costs. Very small threads also add to costs, as they require hand tapping, which adds time and risk.
Instead, limiting your depth to three times the hole diameter and sticking to standard tap sizes in your design can help with CNC machining cost reduction. For example, your design may request 3-48 taps, but shifting to 4-40 taps, a more common size, could save you money. Also, try to keep threaded holes greater than 2-56 inches.
When it comes to tapped holes, two factors that can add cost are hole depth and tap size.
Typically, increasing the length of thread in a hole does little to hold the bolt tighter. It’s really just the first two or three turns that do all the work. As a result, you don’t need to thread a hole to more than 3X the hole’s diameter (and keep it shorter, if possible). Going deeper just increases the risk of tap breakage and adds time to the tapping operation.
In addition, utilizing standard tap sizes can help cut down on costs. For example, 4-40 taps are more common and generally available than 3-48 taps. In the same vein, avoid very small threaded holes, if possible. Anything smaller than a 2-56″ requires hand tapping, which adds significant time and risk to the process.
16.Avoid Small Features With High Aspect Ratio
Any parts that have extreme width-to-depth ratios are usually difficult to machine. For example, small features that have a high width-to-height aspect ratio are difficult to machine because they are prone to vibrations. As with many of the other aspects of machining, if it’s tough to machine, it drives the cost up.
To reduce CNC machining costs, design all features with a width-to-height aspect ratio that’s less than four and consider connecting them to a wall or adding brace support to improve stiffness.
Small features with a high width-to-height aspect ratio are prone to vibrations and are thus difficult to machine accurately.
To minimize cost:
- Design features with a width-to-height aspect ratio of less than four.
- Add bracing support around small features or connect them to a wall to improve their stiffness.
17.Order Larger Quantities
The number of parts you order has a significant impact on the unit price. What’s known as the economies of scale can be a powerful tool as you figure out how to reduce costs. Increasing the quantity from one to 50 could decrease the unit price by more than 50%.
Consider ordering a higher quantity the next time you place an order.
In CNC machining, quantity greatly affects unit price. This is because start-up costs are relatively high and, when quantities are small, they represent a big percentage of the cost. With large quantities, however, the per-unit costs decrease.
In the graph below, we plot the average unit price of 12 different parts machined in stainless steel 304.
The drop in unit price is almost exponential, meaning that even increasing the volume from one to five can cut the unit price in half. Also, ordering very high volumes (> 1,000 parts) reduces the unit price by five to 10 times.
To minimize cost:
- Take advantage of economies of scale by ordering higher quantities.
One of the best and easiest ways to reduce CNC machining costs is to increase the production volume. When the volume increases, the fixed costs of the process are divided across a high number of CNC machined parts. This leads to a vast reduction in the manufacturing cost per part.
One of the major factors that benefit from large production runs is the resulting reduced design costs for parts made by CNC machines. One design blueprint will be utilized for producing 100, 1000, or 10,000 parts. This results in a lower machining cost per product.
Although modern CNC milling machines can combine multiple operations to run efficiently, they still need programming and setup.
Ordering multiple quantities of the same part helps generate production efficiencies and lower the cost per piece.
At the production phase (up to 10,000 parts), CNC machining can provide maximum cost-efficiency.
18.Cut Down on Machining Time by Working with Feasible Materials
Saving on machining time is the ultimate goal in CNC milling planning.
Machining time generally depends on two factors: raw material and part design.
As already mentioned in tip 1, selecting machinable materials, like aluminum, can help reducing machining time and avid tool breakage.
Simplifying the design specification is another great way to optimize the milling operation and save time and money.
Machinability refers to the ease with which a material can be cut. The higher the machinability, the faster a material can be CNC machined, thereby lowering cost. Machinability depends on the physical properties of each material. Typically, the softer and more ductile a metal alloy, the easier it is to machine.
C360 brass is the alloy with the highest machinability, allowing for high speed machining. Aluminum alloys (e.g. 6061 and 7075) can also be machined very easily, though require slightly lower speeds.
Stainless steel has 10 times lower machinability than aluminum and will take at least twice as much time to machine. Different steel grades have different machinability. For example, 304 stainless steel has a machinability index of 45 percent, while 303 stainless steel (an alloy with very similar chemical composition) has an index of 78 percent, making it easier to machine.
The machinability of plastics mainly depends on their thermal properties and stiffness because they are prone to melting and bending during machining.
POM 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.
To minimize cost:
- If you have options, choose the material with better machinability, especially for larger orders.
19.Using Cheaper Materials
As we noticed in the materials cost list, stainless steel 304 block costs $90 while a block of ABS plastic costs just $17. This means that a stainless steel part will be at least $73 more expensive than its plastic counterpart based on the choice of material alone.
For this reason, it is advisable to switch to cheaper plastic components for your production wherever possible. Plastics such as CNCchinese can provide more than sufficient strength required for most cases, providing the most value for money.
20.Outsource to a Trusted Manufacturer
There are many options when it comes to CNC machining companies. However, not every machine shop is the same. A good one will not be the cheapest, but it will provide you with the best value for money and results.
Many machine shops offer a lower milling cost per part but compensate for it by reducing the quality of the operation. Therefore, while they sound like a good deal at first, you may regret it later when you receive the parts and find them of unacceptable quality.
To solve the price vs. quality issue, find a trusted manufacturer that can deliver the quality and price you need.
21.Minimizing Bulk Material Removal:
Sometimes part design changes can have a drastic effect on the amount of material removed from a part. Most parts are made from bar stock, which starts as a rectangular or cylindrical shape. The amount of stock removed has a direct effect on the price of your design.
Think of the smallest box that would fit around your finished part (this can be rectangular or cylindrical, whichever fits your finished part best). The volume inside the box which does not contain your part represents the material that will need to be removed to manufacture your part. The more “empty” space you have means the more material will need to be removed, which in turn will drive up the price to machine your design. There are certain shapes that result in less empty space and modifying your designs towards these shapes can reduce costs.
22.Avoid Deep Pockets
Parts with deep internal cavities are often time-consuming and expensive to manufacture.
The reason is that these designs call for fragile tools that are susceptible to breaking during machining.
To avoid this, either an end mill must be progressively “stepped down” in smaller and smaller increments to reach the desired specs, or other forms of machining, such as broaching or a wire EDM can be used; however, these can be just as costly.
As a best practice, we suggest parts with lengths up to 4X their depth. Anything greater than that becomes exponentially more expensive to manufacture.
23.Avoid Text Until Molding
Similarly, text engraving is an aesthetically pleasing but time-intensive operation, one that might be best to avoid if possible. Here again, a ball end mill is used to trace whatever letters, numbers, and symbols are called for on the CAD model. It looks great, and might be a valid requirement on your machined part, but is probably more appropriate on injection-moulded parts, where additional machining time is amortized over higher part volumes. Because of our toolsets for metals vs. plastics, we have a minimum feature size of 0.035in (0.90mm) in metals and 0.020in (0.51mm) in plastic.
24.Avoid multiple surface finishes
Surface finishes improve the appearance of CNC-machined parts and their resistance to harsh environments, but they also drive up cost. Requesting multiple surfaces finishes on the same part further drives up cost because it requires extra steps (for example, masking the surfaces). An article summarizing the benefits of each surface finish for CNC parts can be found here .
To minimize cost:
- Choose the “as machined” surface finish.
- Request multiple surface finishes only when absolutely necessary.
25.Account for blank size
The size of the blank—that is, the stock material—may impact the overall cost. As a rule of thumb, the blank must be a minimum of 3mm larger than the end part. To ensure accuracy, some material must be removed from all edges of the part.
As an example of how the blank size affects pricing in CNC, consider designing a part that has an envelope of 30 x 30 x 30mm. These dimensions would require a larger blank to be used, which in this case is typically cut from a sheet that is 35mm thick. If the part had an envelope of 27 x 27 x 27mm, however, then a 30mm sheet could be used, saving a lot of material.
To minimize cost:
- Design parts that have a dimension 3mm smaller than a standard blank size.
Conclusion
CNC machining is expensive due to the complexity of equipment and the machine operator’s salary. However, once you get the hang of the process, optimization of cost is quite easy. With an optimized process, the costs and quality of CNC machining are impossible to beat.
To utilize time and resources, most manufacturers choose to outsource their CNC machining process to a third-party company such as CNCchinese, which already bears the most significant cost by investing in the most hi-tech multi-axis machines.
Get in touch with CNCchinese and receive a quote for your CNC machining project today.
Best practices for lowering CNC costs
In conclusion, keep your CNC machining simple.
Complexity has a high price in CNC. Geometries that require special tooling or fixtures, multiple machine setups, or special materials cost more.
So to keep costs down, before you submit an order for quoting, ask the following questions:
- Is my part optimized using designing for machinability guidelines?
- Are all features in my model absolutely necessary? Or can I remove or simplify while retaining the part’s full functionality?
- Can my design be separated into multiple parts that are easier to CNC machine and assemble later?
- Is there a way to modify my design to eliminate the need for multiple machine setups or special tooling?
- Is there a material that is less expensive or easier to machine that can fulfill my design requirements?
The present & the future of CNC machining
The capabilities of CNC machining are constantly expanding. For example, recent advances in CNC tooling enable modern CNC systems to thread holes throughout their length, and holes of any diameter can be CNC machined, without a significant effect on the price, by using a plunging CNC tool and using profile interpolation (i.e. a helical tool path).
In this article, we focused on general designing-for-manufacturability tips that have a universal application, no matter what CNC system is used. Interpret these tips as general good practices that can help you design parts more efficiently.
