We attach great importance to customers' needs for product quality and rapid production.
We always insist that meeting customers' needs is to realize our value!
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+86 133 9281 9446
+86 133 9281 9446
May. 15, 2025
Leo Lin.
I graduated from Jiangxi University of Science and Technology, majoring in Mechanical Manufacturing Automation.
Did you know that the cost of the wrong manufacturing method is a significant drain on design and development resources—isn’t that approximately 60%?
When you have a need for precision metal parts, durable prototypes, and the lowest cost for medium volume runs, it is important to know the variability between CNC machining, 3D printing, and injection moulding.
No manufacturing method is perfect, and they all entail compromises. 3D printing can be a great manufacturing method for prototypes as it is fast, but a really bad manufacturing method for functional parts. Injection moulding has lower pricing for higher volume production, and after that, you have the investment. CNC machining brings the best combination of abilities to construct precision parts using materials, and “no surprises” for low or mid-volume production.
The right manufacturing process will clearly affect your costs, quality and leadtimes. CNC machining, 3D printing, and injection moulding all have advantages, disadvantages and specifications. Once you know how they differ, you will be able to compare and select CNC machining against 3D printing and injection moulding for making parts and prototypes.
CNC machining is a subtractive manufacturing process; a solid block of material is placed into a CNC Machine, and material is removed using computer-controlled tools. Technically, CNC machining can achieve tolerances as tight as ±0.001 inches; CNC machining is an effective way to manufacture precision parts, mostly metals like aluminum and steel, and some engineering plastics. Industries like aerospace, automotive, and medical devices continue to make functional prototypes and end-use parts with CNC machining because they know they will work with complex geometries and have strength and surface finish.
3D printing manufactures parts by building them layer by layer, using polymer, resin or metals. Additively manufactured parts are made for “rapid prototyping” where designers can develop design iterations and do it quickly, while having the potential to complex internal structures. However, the parts are often weaker and less durable than machined parts. While some industrial 3D printing processes are metallic, most applications deal with plastics to make concept models, custom parts, and low-stress functional parts.
Injection moulding uses pre-made moulds to force molten material into shape. This allows for the fastest production of plastic parts with high volumes. The mould costs are high in the beginning, often around $10k or more, but once the moulds are made, the manfuacturing costs per unit drop substantially with large orders. This is especially prominent in consumer products, enclosures for electronics, and single-use medical products. Since changes to the design are expensive once the moulds have been created, it is best suited to mass production of finalized products.
If you want material diversity, tight tolerances, and a middle ground on volume, CNC machining services are more ideally suited to meet your needs. If you require speed and low-cost prototypes, 3D Printing is a good fit. Injection moulding is by far the most efficient method for producing large volumes of plastic products but will require a large upfront fee!
When precision and material diversity are most important, CNC machining is superior to alternative manufacturing methods. It offers unmatched accuracy while supporting a breadth of materials, making it great for functional prototypes as well as final-use parts.
CNC machining can achieve tolerances of ±0.001 inches, giving assurance each component is built to specifications. Unlike 3D printing inability to produce stable dimensions, CNC machining is capable of maintaining tolerances with metals like aluminum and titanium, even engineering plastics (like ABS and PEEK). This is extremely valuable component manufacturing for the aerospace and medical sectors as both require resistance to heat and overall structure. Excellent for Prototypes and small batch production
3D printing allows for functional models on a conceptual process while CNC machining will allow us to produce functional prototypes that have equivalent strength and performance as the final product. CNC machining lends itself well to small batch production often less than 10,000 pieces, and can see efficiencies and cost savings versus injection moulding. Also remember CNC does not involve moulds therefore there will also be less lead times with CNC, less cost should there be need for design changes, and there may not be any tooling that has been involved within the CNC process.
CNC machining is ideal for companies who are dealing with high levels of accuracy, durable materials and require scalable services both on performance and price.
CNC machining, 3D printing, and injection moulding all have advantages and limitations that can restrict design or reduce efficiencies in production. Understanding the limitations of each process, will take time, but it will provide the manufacturer clarity as to which process is best suited for fit their project constraints.
CNC machining is limited by its geometric capabilities, which are constrained by the limitations of a subtractive process. Rolls, for example, will usually require some form of radius on internal corners because no tool can mill a true 90 degree angle. Also, depths of pockets or a complex five-axis design will drive increased machining times and therefore costs, plus CNC machining wastes material removing unwanted surplus to achieve the desired net shape.
3D printing is just as good process type for speeds to make prototypes, however, it cannot replicate any of the construction application advantages of machined components. Most standard printers can only print with plastics or resins that don’t have the strength to build parts that will be under high stress. Surface finishes often need to be sanded or polished to achieve smooth or aesthetically pleasing results.
Injection moulders have a great throughput in high volume production, with high start up costs to producing a mould. Custom molds are often $10,000+ and would not make economic sense to use at low volume. Once the mold is made, any adjustments or changes they are costly and take time.
Choosing between CNC machined, 3D printed, or injection moulded comes down to three key elements; volume, time-to-market or delivery date, and budget.
CNC machining is a good option for a production run of 10-10,000 pieces as it provides, what is required for safety critical metal parts in terms of precision, producing tight tolerances, while avoiding the need for expensive custom moulds. CNC machining has lead time is usually 3-7 days, therefore it is evenly distributed across projects in their timing, cost, and mechanical or thermal properties likely to be required should the properties or quality be critical to the success of the project.
3D printing provides the quickest turnaround (1-5 days) for concept models and prototypes, and injection moulding will only be more economical when producing a massive number of parts (10,000+) and you have found a way to recover the high cost of the custom molds and lower your cost per part. If the only requirement is plastic mass production with inflexible designs, you will not find a lower price for plastic per part than injection moulding.
Materials have a direct impact on part performance, cost, and ability to manufacture. Each of the manufacturing methods will have its own capability restrictions or allowability of certain materials, and this will affect the success of your project in many ways.
CNC machining has the greatest selection of materials available as a result of many factors:
● Metals: Aluminium (lightweight), stainless steel (rugged), titanium (strength-to-weight)
● Plastics: Nylon (wear resistant), POM (dimensional stability), PEEK (very high temperature)
● Composites: Fiber-reinforced materials for specialized uses
This range of materials gives CNC machining versatility and allows it to be the best option for functional prototypes and end use parts that require specific mechanical properties or thermal properties.
3D printing can only use thermoplastics (PLA, ABS, etc…), and resins (dimensional stability) for structural parts. 3D printing in metals exists but is usually only feasible for very high cost applications. Injection moulding is limited to only standard thermoplastics (PP, PVC) standard thermoplastics and is difficult to switch any materials to completely different materials; new molds would be required limiting your design flexibility to modify production parts.
Realizing volume thresholds will help people conceptualize real economic options when assessing one process over another.
For production volumes below 10000 units, CNC machining provides the best value because of:
● No mold costs
● Consistent parts cost
● Fast lead time (3-7 days)
CNC machining provides the ideal solution when projects are attempting the bridge the production gap between prototyping and mass manufacturing.
At 10000+ units, injection moulding is economical, given:
● Dramatically lower part cost
● Fast cycle times on identical parts
● Enhanced consistency in surface finish quality
Injection moulding provides the true mass production option where the costs of the upfront molds provide an assured lower per piece cost-- you cannot beat injection moulding.
When quality and versatility matter most, CNC machining stands out as the superior manufacturing solution. Unlike 3D printing’s material limitations or injection molding’s high upfront costs, CNC delivers:
● Precision (±0.001" tolerances)
● Material flexibility (metals, plastics, composites)
● Cost efficiency for 10-10,000 unit runs
For functional prototypes, aerospace components, or medical devices requiring reliability, CNC machining ensures production-grade results without compromise.
Ready to start your project? Contact CNKAIERWO for expert CNC machining services tailored to your specifications.
We attach great importance to customers' needs for product quality and rapid production.
We always insist that meeting customers' needs is to realize our value!
