Can metal 3D printing completely replace traditional mold manufacturing methods?

一, The main difference between additive and subtractive production from a technical point of view
"Digitally driven layer by layer melting and stacking" is what metal 3D printing is all about. As an example, laser selective melting (SLM) melts only certain types of metal powder using high-energy laser beams. It then builds three-dimensional shapes layer by layer and makes complex internal spaces, conformal cooling channels, and other structures directly without the need for moulds. Platinum Technology created a biomimetic vein-shaped waterway for the mould of new energy vehicle battery boxes that has cut the injection moulding cycle by 35% and improved cooling efficiency by 40%. This is hard to do with standard drilling and milling methods.
Traditional mould making, on the other hand, uses "subtractive processing" (like CNC milling and electrical discharge machining) and "equal material forming" (like casting and forging). The way these processes work means that mould design needs to take processing feasibility into account. For example, in traditional die-casting moulds, the cooling water channel is often broken or straight. This is because the drill bit is hard to get to and it's hard to make a design that fits the mould hole. This makes the cooling uneven and causes products to deform by more than 8%.
The most important point of technological substitution: 3D printing is the only way to go when the complexity of the mould structure (internal cross holes, thin-walled ribs, microchannels, etc.) makes traditional methods impractical, or when design changes need to be made quickly. For instance, 3D printing cut the time it took to make a medical device shell mould from 6 weeks to 72 hours, and it increased the rate at which materials were used from 25% to 95%.
二, Cost Structure: Business Turnaround in Small Batch Situations
Mould development costs make up as much as 60% to 70% of the total cost of traditional mould making. These costs include the wear and tear on equipment and the labour needed for electrode production, electrical discharge machining, wire cutting, and other processes. "Direct moulding of digital models" in metal 3D printing gets rid of the need for moulds, and the main things that determine its cost are the powder materials used and the wear and tear on the equipment.
1. For small batches (1–100 pieces), 3D printing is clearly better.
The amount of material used: In traditional methods, like forging and blank cutting, up to 70% of the material is wasted. But in 3D printing, the leftover powder can be recycled, so over 90% of the material is used. As an example, 3D printing cuts the cost of materials by 58% for a certain aluminium metal die-casting mould.
Processing cost: Traditional moulds need several machines to work together to process them, but 3D printing only needs one machine to do the core structure moulding, which cuts processing costs by 40% to 60%.
Cycle time: The standard mould opening cycle can take up to six to eight weeks, but 3D printing only takes three to five days. This can cut the R&D cycle by more than seventy percent, making it perfect for the verification stage of trial production.
2. For large orders (more than 1000 pieces), traditional workmanship is still the norm.
Unit cost: As output goes up, the shared cost of traditional moulds goes down very quickly. For instance, when a lot of car hood moulds were made, the price per piece dropped from 2000 yuan for 3D printing to 80 yuan for old-fashioned methods.
Precision and surface quality: With traditional CNC cutting, you can get a surface that is 0.8 μm flat, but with 3D printing, you have to go through polishing, sandblasting, and other steps to get a surface that is 3.2 μm flat, which costs more.
When the annual production of moulds goes over 500 pieces, the cost of a single piece using traditional methods starts to be lower than that of 3D printing. If the risk of design changes is taken into account (for example, changing a traditional mould means opening it again, which can cost up to 30% to 50% of the initial cost), the benefits of 3D printing in flexible production can be extended to situations where around 1000 pieces are produced each year.
三, Industrial ecology: how technology can work together to help the environment and how it can be rebuilt
Traditional mould making and metal 3D printing are competing with each other, but it's not a zero-sum game. Instead, it's a force that's pushing the industrial environment towards "design manufacturing service" integration.
1. Combining technologies: making composites with additive and subtractive methods
Companies that are at the top are breaking through the limits of a single technology by using "3D printing+CNC precision machining" together. Platinum's BLT-S450 equipment, for example, can do six-laser collaborative printing and a five-axis machining centre can repair mould cavities with mirror-level accuracy. This keeps the complex structural capabilities of 3D printing while meeting the surface quality needs of traditional moulds.
2. New Materials: Functional Gradients and Composite Materials
The materials used in traditional moulds are mostly single alloys. However, 3D printing can place functionally graded materials in a way that is unique to each job. In the case of an aeroplane engine mould, 3D printing adds a high-hardness coating (like WC Co) to the surface. This keeps the core tough and makes "one material for multiple uses" possible, which is an improvement over the old way of connecting different materials together.
3. Service mode: from selling devices to delivering solutions
"Hardware suppliers" are changing their names to "service integrators" for equipment makers. Platinum has released a "equipment+materials+process database" system that works together. Its self-made titanium alloy powder prices are 50% less than they were in 2020, and the Internet of Things platform has made it possible to remotely diagnose and warn about equipment faults, which has increased the service revenue to 30%.
4. Standards in the industry: From wild growth to standardised development
Traditional mould making has created a full standard system, such as the ISO 2768 mould accuracy standard. However, 3D printing moulds still have problems, like not being able to get accuracy approval and control their defect rate. For example, medical implant moulds need to be certified by both the FDA and the CE every three to five years. This makes it harder for 3D printing to spread to high-end areas.