Supply chain management is a constant juggling act. It must balance overall inventory, local availability, and variations in demand. If managing these factors is already a challenge for new products, then spare parts represent the ‘perfect storm’. Maintenance programs and quantities may be designed into a product life cycle. However, they are not always followed. And who knows when and where breakdowns will occur? And what the need for parts will be from one day to the next?
Faced with these unknowns, suppliers may have few valid options. They can bulk up on spare part stocks, but inventory costs money. It costs even more when suppliers multiply stocks to maintain them locally for specific customers. If people’s wellbeing or business continuity are in the balance, distributed stocks of spares may be mandatory. The cost then often finds its way onto the invoices for the customers. Otherwise, suppliers may try to duck the issue by holding a smaller quantity of parts centrally or only making them on demand. Costs may go down, but so too does customer satisfaction as delivery times stretch out.
Forecasting and inventory for spare parts are indeed thorny problems. But finding solutions is not the only option. In some cases, you can also simply cancel out the problems. The magic wand for making them disappear is called 3D printing. This is a form of supply that takes traditional warehousing and demand planning out of the equation. The two common ways of making things using 3D printing are as follows.
The first way is fused deposition modelling or FDM using plastic. The 3D print head heats the plastic. It then sends it in fine, targeted jets to build up or ‘print’ the object layer by layer. The 3D printer can build solid or hollow forms, as well as convex and concave ones. The second way is selective laser sintering or SLS. In this case, the 3D printer uses a powder form of metal, plastic, ceramic, or other material. A laser beam heats the powder selectively to form the 3D object required. Between these two processes, there is little that cannot be 3D printed, on demand, and wherever a 3D printer is located.
These capabilities mean three levels of opportunity using 3D printing for spare parts and supply chains. They range from tactical, short-term advantages to strategic, longer-term improvement.
Opportunity level 1 – Tactical and logistical
3D printing is software driven. It uses virtual electronic models to print as plastic or metal objects. In this sense, it is like traditional printers that print electronic documents onto paper. Virtual models can be stored in a computer database. There is then no need to store physical objects in a physical warehouse. The only physical item to be stored is the raw material for printing. This is the fusible plastic or packs of small metal beads, for example.
Parts and products can then be 3D-printed on demand. This solves the issues of unpredictability and inventory. Waste is also limited by the efficient manufacturing process. 3D printing is an additive process. It works by building a product precisely, layer by layer. On the other hand, traditional manufacturing is subtractive. It involves the removal of material that often becomes scrap.
Costs must also be correctly compared, if 3D printing is to justifiably replace traditional manufacturing.
In addition, 3D printing offers advantages and options for managing availability. It avoids the delays and expenses of tooling up production lines. As 3D printers come down in price, they can increasingly be located directly where parts are needed. Transport costs fall away. The only item that needs to travel is the virtual model to be printed. This is an electronic file that can be sent over the internet. Building on this idea, a further option is to use third parties to print locally and even to send the file directly to a customer with 3D printing facilities.
However, costs must also be correctly compared, if 3D printing is to justifiably replace traditional manufacturing. The production cost per item in 3D printing may still be higher than that of an optimised standard production line. The speed of production per item may also be slower. 3D printing is not yet a solution for mass production. There may be additional cost factors like the machining, milling or coating of parts from 3D printing.
The savings are in the reduced or zero inventory needed. Also, overall lead time is low for making and supplying spare parts. Savings can be made in the reduced downtime of the systems needing the parts. Comparing these pros and cons will be a first step in deciding if or how much 3D printing makes sense.
Opportunity level 2 – spare part and product redesign
The ideas above already offer logistical cost reductions and faster time to availability. The next step is to improve performance inside the products and spare parts themselves.
Products designed for 3D printing can offer greater strength and lighter weight. Computer design software allows the modelling of any shape or form. This includes models with hollow honeycomb structures inside to reduce the total mass without sacrificing stability. 3D printing allows such structures to be manufactured like any other shape. Parts with overhangs can be made layer by layer too. The printing process then includes a separate phase to create the support for the overhang (the ‘scaffolding’ beneath). After the entire product has been printed, the support can be removed.
Smarter design can take things further still. One jet engine manufacturer is using 3D printing for engine nozzles. It now prints one part, instead of assembling from many. Reliability and performance are as good as before, if not better. The number of component suppliers goes down. Risk goes down. The operation is more streamlined and life for procurement team becomes easier.
For decisions on which products and parts to move to 3D printing will depend on various factors.
Better inherent product performance can be made a priority too. Weight reduction lets aircraft use less fuel, saving on CO2 emissions. In certain cases, 3D printing does what traditional production methods like die casting cannot. Designs can then extend offer improved fuel flow and, easier, faster maintenance. 3D printing can help simplify where appropriate. It can also support additional complexity if needed.
As a bonus, 3D printing for spare parts can help prolong the useful life of older machines. Spare parts produced conventionally may no longer be available. However, the part can be modelled in software for 3D printing in the material required (metal, plastic, ceramic, resin, and so on).
Decisions on which products and parts to move to 3D printing will depend on various factors. Product data can be collected from different supply chain and production systems. A product lifecycle management (PLM) system will have technical drawings, manufacturing plans, and information on possible innovation. An ERP system will offer access to quantities, costs, and current suppliers. The return on investment for converting to 3D printing and possibly reengineering can be calculated in each case. Working in other factors such as safety and reliability, the possibilities can be ranked and acted on.
Opportunity level 3 – supply chain reengineering
Why stop at redesigning the parts that travel through the supply chain? 3D printing also offers the chance to redesign the supply chain itself. 3D-printed parts can be made immediately available in practically any location. One forward looking building company in France built a small house using only 3D printed components. All it takes is two things. First, a 3D printer installed on site. Second, a network connection to download the file with the model to be printed out. From a spares point of view, supply chain operations can reduce or eliminate warehousing and shipping. Demand forecasting becomes a matter of how much fusible plastic (or metal, etc.) to buy. As more parts are 3D-printed, the overall requirements for plastic print material are smoothed. Buffer stocks of print material can be kept low overall. Alternatively, suppliers with proven supply reliability and performance can deliver just in time. The bullwhip effect of huge safety stocks becomes a thing of the past.
Ultimately, 3D printing could transform some supply chains from purely physical to entirely electronic.
Also, product supply can become more flexible, more tailored. 3D product and part manufacturing can be profitable at low volumes. A product run of one unit becomes feasible. Enterprises can supply on demand. Their products are no longer stored in warehouse racks, but in a database of electronic models. Where appropriate, models can be adapted to individual requirements. Customer needs, whether at a personal or organisational level, can be met with increased precision. Postponement strategies become more flexible too. The customisation of products can be done later along the supply chain. It can even be done at the end of the delivery chain, with 3D printers in regional distribution centres, not just in a central manufacturing facility.
Ultimately, 3D printing could transform some supply chains from purely physical to entirely electronic. Some customer enterprises already have 3D printers for their own needs, such as making product prototypes. In this case, they could pay for the use of a part or product model that they would then print out directly on their site. Digital licencing techniques already exist for intellectual property of many kinds. 3D spares printing can use the same mechanisms or others to ensure vendors are paid according to the number of spares units printed.
Challenges of 3D printing for supply chains
While the vision is clear, some real-life issues must still be solved. 3D printing can cross borders in ways that physical products cannot. A computer file sent over the internet is undetectable by customs authorities. While this means part and product delivery in minutes, perhaps also saving on import duties, it also nullifies the watchdog role of customs. It is no longer possible for customs authorities to check for suitability for consumers and safety, for example.
Counterfeit goods cannot be identified like before. Counterfeiters of electronic product blueprints cannot be pursued in the same way. Yet the 3D printing market is bound to attract copiers and fakers. Manufacturers may seek to protect their blueprints through digital copy protection. Note however, by scanning a product in three dimensions to reverse-engineer a product design, fakers can also make their own blueprints.
Issues of liability may arise. What happens if a 3D printed product breaks after being printed outside the original manufacturer’s premises? 3D printing service providers will first need to be checked for proper standards of printing and finishing. Customers printing on site will need print installations that comply with manufacturer directives. Alternatively, they might need to waive certain rights or claims. Manufacturers and vendors will also need to keep a tight grip on their product change process. The adaptability of 3D printing can be double-edged. The ease of modifying a product or part and printing it right after could lead to chaos in installed bases otherwise.
Conclusion
3D printing for spares and products is still a new supply chain concept. It has potential in several ways. It can make spare parts logistics more efficient with faster delivery. It can also turn traditional warehousing and shipping on their heads. 3D printing will become a competitive weapon in supply chains, to a certain degree. That said, some suppliers will continue with traditional parts and products manufacturing and delivery. This may be because some parts are still better made using conventional methods. It may also be because there is a strong service component that lessens the impact of 3D printing. Note also that 3D-printed parts are not automatically greener than their conventional counterparts. Only an assessment of the overall effect on a supply chain and customer use will show if they are better for the planet.
In studying the feasibility of 3D printing, organisations should consider other factors too. Laws are still lagging the advances in 3D printing. Changes in regulations could alter the business case for 3D printing. Enterprises will therefore also need to keep an open mind. This applies to opportunities for themselves. It also applies to new forms of competition, whether licit or illicit. In summary, 3D printing with all the aspects described above merits a thorough evaluation and clear thinking. Only then can you be sure that using that extra dimension will bring benefit and not disorder.