How to combine metal 3D printing and mold injection molding?

一, The main idea behind technological integration is to go from "substitution" to "complementarity."
Metal 3D printing and injection moulding are not just two technologies that work together; they are a mix of "additive manufacturing" and "subtractive processing" that works together to improve efficiency and functionality. The following three things show its main logic:
A big step forward in design freedom
Conventional injection moulds are restricted by processing methods, and intricate designs like conformal cooling water channels and internal reinforcing ribs necessitate distinct production and assembly processes, leading to elevated prices and extended cycles. LPBF technique can directly print integrated complicated structures by melting metal powder one layer at a time. For instance, laser technology has created the third-generation breathable steel process, which can make multi-directional breathable structures with a 0.04mm aperture in moulds. This solves the problem of typical breathable steel inserts not being very good at letting air out.
Finding the right balance between cost and efficiency
It costs a lot to buy the equipment for metal 3D printing, but it can help reduce material waste (with a material utilisation rate of over 90%). Businesses can utilise 3D printing to make the core functioning elements of moulds (such conformal cooling inserts) and traditional processing to make peripheral structures. This cuts costs by a lot. For instance, B&J Speciality uses 3D Systems' ProX DMP 300 to print automotive pipeline mould inserts. This cuts the cooling cycle time from 1 minute to 40 seconds, boosts production efficiency by 30%, and extends the life of the mould by 25%.
Quick changes and making things to order
Metal 3D printing can swiftly make mould prototypes for testing and verification during the product development stage. This cuts down on the cost of making changes to the design over and over again. For instance, a company that makes household appliances uses LPBF technology to make injection mould pattern blocks for air conditioning shells. This cuts the traditional 12-process, 45-day cycle down to 12 days and lowers assembly errors from 0.1mm to 0.02mm, which extends the life of the mould by 200,000 times.
二, Common use cases: from improving functionality to upgrading industry
1. A flexible cooling system is the best way to fix problems with injection moulding.
Most of the time, the cooling water circuit in typical injection moulds is straight, which makes it hard to match the product's surface. This causes uneven cooling and product deformation. LPBF technology can make a conformal canal that fits the shape of the object perfectly, which cools it evenly. For instance:
Automotive pipeline mould: Using Cimatron software, B&J Speciality built a conformal cooling water circuit that lowered the temperature of the mould from 132 to 18 degrees Celsius, cut the shrinkage rate of the product by 67%, and raised the yield to 98%.
A dentistry company makes invisible orthodontic appliance moulds using μ - LPBF technology, which has a printing precision of 2–5 μ m. Topology optimisation design improves the homogeneity of orthodontic force distribution by 40% and raises the patient adaption rate from 85% to 98%.
2. To fix the problem of trapped gas, the breathable structure and mould body must fit together perfectly.
If the gas inside the mould cavity is not released quickly enough during the injection moulding process, it can cause problems including product bubbles and poor fusion. The classic method calls for putting breathable steel in the mould, however it doesn't work as well when the structure is complicated. LPBF technology can print porous, breathable layers directly onto the mould body. For instance:
Gas-assisted forming mould: A specific company employs LPBF to print mould cores, creates a porous layer at the bottom of the rib plate, and embeds a ventilation rod with a porous top layer. Gas pushes down on the rib plate and the top of the ventilation rod during injection moulding. This pushes the product towards the cavity surface, which gets rid of internal stress and stops shrinkage lines on the surface.
Electronic moulds with high accuracy: A 3C product mould manufacturer makes mobile phone frame moulds using LPBF. The moulds have a breathable structure with a 0.04mm opening in the exhaust area, which lowers injection pressure by 30% and extends mould life by 40%.
3. Lightweight and functional integration: from "structural components" to "intelligent modules" LPBF technology supports lightweight design such as lattice filling and lattice structure, and may integrate functional modules such as sensors and heating elements. 3. Lightweight and functional integration: from "structural components" to "intelligent modules" As an example:
A particular company employs an aluminium alloy bracket made by LPBF for their new energy vehicle battery pack. The bracket is 38% lighter because of its lattice structure and passes a 150% overload test, which increases the range by 8%.
Smart mould system: A medical company puts temperature sensors inside LPBF-printed moulds so they can keep an eye on the temperature of the cooling water circuit in real time. AI algorithms change the injection parameters on the fly to make the product 50% more consistent.
三, Technological Problems and Trends for the Future: From "Single Point Breakthrough" to "Ecological Restructuring"
1. Current problems: materials, accuracy, and post-processing
Some metal powders, including copper alloys with strong heat conductivity, still need to be optimised for printing so that density and cost are balanced.
Surface quality and accuracy: LPBF printed moulds need CNC precision machining or shot peening to meet the surface roughness (Ra<0.8 μ m) criteria for injection moulding.
Integration of several materials: LPBF now only supports printing with one material at a time. However, moulds typically need composite constructions made of different materials, like high-hardness steel and high-thermal-conductivity copper.
2. Future Trends: Merging of Technologies and Restructuring of the Environment
Hybrid tools for making things: AXIOM technology combines 3D printing nozzles and CNC milling cutters to provide "additive subtractive" integrated processing. This cuts down on the size and expense of the equipment needed to do the job.
Smart process optimisation: LPBF can anticipate residual stress and deformation in real time by combining thermal mechanical coupling models with machine learning methods. For instance, Autodesk's finite element model keeps the differential in radial and circumferential tensile performance of titanium alloy turbine blades within 5% and makes them last 30% longer.
Green Manufacturing and Circular Economy: LPBF recycles more than 85% of its powder, and it doesn't release any cutting fluid, thus it meets green manufacturing regulations including the EU's "carbon tariff." One company cut the cost of a single set of mould materials by 20% by recycling powder that hadn't melted yet and screening it.