What is the proportion of post-processing after metal 3D printing in the overall manufacturing cost?

一, The parts that make up post-processing charges and their main parts
There are four main technological modules that make up the post-processing of metal 3D printing: material removal, heat treatment, surface treatment, and structural strengthening. Each module has costs like equipment, energy use, and labour.

Taking away materials: this includes taking away the support structure, completing the surface, and fixing the dimensions. For example, following printing, the surface of the flow channel on aviation engine blades needs to be mirror polished using a five-axis linkage machining centre. It can take many hours to produce a single piece, and a large part of that expense is for equipment and labour.
Heat treatment is the process of getting rid of internal stress and improving the structure of the grains. This can be done through annealing, solid solution+aging, and hot isostatic pressing (HIP). Vacuum annealing treatment reduces residual stress by 80% after printing a titanium alloy orthopaedic implant. However, it needs a special vacuum furnace and long-term insulation, which makes up a large part of the energy expenditures.
Surface treatment: methods include sandblasting, electroplating, laser cladding, micro arc oxidation, and others that cover the surface. After printing the bracket for a new energy vehicle battery pack, micro arc oxidation treatment increased its resistance to corrosion in the salt spray test to over 1000 hours. However, the cost of chemicals and equipment maintenance was rather expensive.
Structural reinforcement, such as fibre reinforcement, gradient material design, and lattice structure optimisation. The printed parts of a certain nuclear power valve use a gradient structure made of nickel-based alloy stainless steel. This requires a composite process of multi-material co-printing and heat treatment. The technical complexity makes research and development and trial production more expensive.
二, Data from the industry and case studies on the percentage of post-processing costs
1. An examination of the cost structure in standard industries
In the aerospace field, for example, the fuel tank frame of a certain rocket engine costs about 40% to print, 35% to post-process (15% for HIP processing, 12% for CNC milling, and 8% for anodising), and 25% to buy materials. The large percentage of post-processing expenses is because parts have to work well in very harsh settings, which means they have to go through many steps to make sure they are reliable.
When it comes to medical devices, the cost of post-processing a custom titanium alloy hip joint implant after printing is about 28% (with heat treatment costing 12%, polishing costing 10%, and sterile packaging costing 6%). The cost of the materials is 35%, and the cost of design and validation is 37%. The percentage of post-processing costs is not very large, but the requirements for surface roughness (Ra < 0.2 μ m) and biocompatibility mean that high-precision machining and specific processing are needed.
In the world of consumer electronics: For example, the printing cost for a folding screen mobile phone hinge scroll is 55%, the post-processing cost is 25% (10% for support removal, 8% for heat treatment, and 7% for surface sandblasting), and the material cost is 20%. The scale effect of mass manufacturing has a big impact on the percentage of post-processing costs. As output goes up, the cost per unit goes down.
2. How the choice of process affects the costs after treatment
The powder bed melting (PBF) process: The percentage of post-processing expenditures is usually significant since support structures need to be added during the printing process. When you use SLM technology to print a given part of an airplane's structure, 30% of the cost is for removing the support and polishing the surface. When you use EBM technology without support structure, this cost goes down to 15%.
The adhesive jet (BJ) process makes near-net forming possible by degreasing and sintering the green body after printing. This cuts down on the expenses of post-treatment by a large amount. After printing a car wheel hub with BJ technology, the cost of post-processing is only 12% (primarily heat treatment and a little machining). This is more than 50% less than the cost of post-processing with PBF technology.
Directed Energy Deposition (DED) process: good for fixing big pieces and getting ready for coating; the cost of post-processing is based on how thick the printing layer is. When the printing layer thickness of a certain mining machinery gear is 1mm, the cost of post-processing is only 8%. But when the layer thickness lowers to 0.3mm, the cost of polishing goes up to 15% because the surface becomes rougher.
三, The elements that affect the proportion of post-processing costs and the best way to change them
1. Examination of motivating elements
Requirements for how materials work: High performance materials such as high-temperature alloys and titanium alloys require HIP treatment to eliminate pores, which can contribute for up to 20% -30% of the total cost.
How complicated the part is: Multi-axis machining and special testing are needed for complex features like internal flow channels and lattice structures. After printing a given aviation engine blade, CT testing costs 25% of the overall cost of post-processing.
Batch scale: In the consumer electronics area, when the volume of a single batch of printing exceeds 10,000 pieces, the percentage of post-processing expenses can be lowered from 30% to 15%. This is mainly because of automated production lines and process solidification.
Technological maturity: The difference in accuracy and stability between equipment made in the US and equipment made in other countries means that 10% to 15% more work needs to be done after processing on US-made equipment, which indirectly raises costs.
2. Looking at the best way to optimise
Process innovation: Using technologies like regional printing and bidirectional powder distribution to make printing more efficient and need fewer supporting structures. One company improved their scanning method to cut support volume by 40%, which also cut the percentage of post-processing expenditures.
Optimising materials: Make specific powder materials that are easy to work with and don't put too much stress on them. A particular company has released a titanium alloy powder with low oxygen concentration. This powder lowers the heat treatment temperature by 50 °C and cuts the cost of energy use from 18% to 10%.
Upgrading equipment: Adding online detection and adaptive processing technologies to cut down on the need for people to do things by hand. A company that uses an AI-powered polishing robot has cut the time it takes to process one piece from two hours to half an hour. The cost of labour has also gone down from 25% to 8%.
Working together in the industrial chain: Integrated printing and post-processing equipment can shorten manufacturing cycles. A specific company has invented a "printing+heat treatment+machining" composite machine that cuts the time it takes to make aviation structural parts from two weeks to three days and lowers the cost by 35%.