3-D printing takes a bite out of spare part storage costs

Additive parts manufacturing increasingly is used to produce spare parts and decentralize parts production, said Marie Thiébault, 3YourMind’s country manager for France and Spain.

3YourMind is a Germany-based company that produces software to help clients manage workflow associated with additive manufacturing, including analyzing which parts are suitable for 3-D printing all the way through management of the production process.

Over the next five years, up to 8 percent of SKUs [stock keeping units] will be a better business case for additive manufacturing than conventional sourcing, Thiébault said.

Thiébault spoke with Plastics Machinery & Manufacturing following a presentation she gave in January for the TIPE 3D Printing conference.

3-D printing spare parts can offer multiple benefits, such as reducing manufacturing costs, decentralizing production, reducing lead time for delivery and improving part performance. It can be particularly cost-effective when a company needs only a small number of spare parts, Thiébault told PMM.

One of the reasons it makes sense for companies to begin printing their own spare parts or contracting with a local service provider to print them is because storage can be expensive, Thiébault said. Companies that don’t print their own tend to keep large numbers of spare parts on hand, because it can take weeks or months to receive replacement parts that might be manufactured halfway around the world.

However, if instead of storing spare parts in a warehouse, a company stores digital files for 3-D printing those parts in a computer, it can print them relatively quickly. For example, a conventional parts supplier might tell a client it would take three months to deliver a spare part, but “we know that in additive manufacturing, the average lead time is 10 days,” Thiébault said.

Obtaining spare parts, especially for older pieces of equipment, can be challenging.

“Sometimes, it is an obsolete part,” Thiébault said. “Sometimes, you don’t know who the supplier is. And when you need spare parts, sometimes it takes three months to get the part. So, all of that showed that 3-D printing can be one of the solutions to basically reduce the cost and reduce the lead time.”

3YourMind has worked with an oil and gas company that wanted to create what it calls a “virtual warehouse,” where it can digitally store 3-D drawings and other digital files needed to print replacement parts that it has purchased from the intellectual property (IP) owners.

One of the first challenges a company faces when it decides to produce parts through additive manufacturing is determining who the IP owner is for the part.

“If it’s the end user, the end user can choose to print the part by himself or he can choose to sign with an external supplier that can print the part,” Thiébault said. “However, if the end user doesn’t have the IP, he has to go to the conventional supplier to ask for the IP, or he has to go to the conventional supplier and ask the supplier to print the part.”

Oil and gas companies may find additive manufacturing particularly attractive because they typically have huge warehouses filled with spare parts, and some of the parts needing replacement may be 30 years old or more.

“They have very old spare parts; they have obsolete, legacy parts,” Thiébault said.

If those parts are no longer manufactured, it can be very difficult and expensive to produce them again, she said. Conventional production might require the creation of tooling, which adds to the cost and the time for delivery.

“AM really can play a role, especially for obsolete parts,” Thiébault said.

The transportation industry also is using metal- and polymer-based 3-D printed spare parts.

“We know that if one part is missing, a train can stop. So, you see that in this case, the lead time is super, super important,” Thiébault said.

It’s not uncommon for trains built 30 to 35 years ago to still be operating, and for railway companies to need replacement parts that may be difficult to locate.

SNCF, the French national railway company, worked with 3YourMind to find a solution for reducing the cost and lead time for replacement parts. The railroad operates passenger and freight trains daily on about 19,000 miles of track, according to the company.

The railroad faced numerous challenges in 3-D printing replacement parts, including a lack of technical information and 3-D drawings, “messy ERP data” for spare parts, and a lack of AM knowledge.

3YourMind’s suite of software helped SNCF solve those problems, Thiébault said.

“We set up a solution to analyze spare parts based on technical and economic data,” she said.

3YourMind software helped SNCF evaluate 30,000 spare parts and determined that 10.3 percent of them were ideal for additive manufacturing. AM parts could be delivered in 10 business days, shortening the average lead time by 2.5 months, Thiébault said. SNCF also will save about 1.1 million euros, or more than $1.3 million, annually.

In SNCF’s case, it initially appeared as if it would be more expensive to purchase AM-produced spare parts than conventionally manufactured ones. However, once the cost for storing conventionally manufactured parts was factored in, the scale tipped in favor of additive manufacturing, Thiébault said.

For each year a spare part is stored in a warehouse, on average, it adds 25 percent to the cost of the part, she said. In other words, after a part is stored for four years, the cost of that part has doubled.

3YourMind’s Agile PLM software recommended three technologies for manufacturing the SNCF’s spare parts: Wire arc additive manufacturing (WAAM) and direct metal laser sintering (DMLS), which are metal technologies, and fused deposition modeling (FDM) for thermoplastic materials.

3YourMind also worked with Deutsche Bahn, the German railway company, to identify metal and plastic parts that could be 3-D printed. One example is clamps that were originally produced through injection molding, but are no longer produced and the tooling is no longer available. The German railroad printed 1,500 braille plates on handrails in train stations to help guide blind commuters. Producing them through 3-D printing saved the railroad 50 percent of the cost of traditional manufacturing.

Deutsche Bahn also uses 3-D printers to produce train headrests, fan propellers, various enclosures, coat hooks and spare parts for coffee machines. The railroad can create spare parts in a short time that otherwise would have long delivery periods or might not even be available at all, according to the railroad’s website. The result is that trains can return to service more quickly.

All 3-D printed components undergo extensive testing before they are used. The first printed components were made exclusively of plastic, usually polyamide, but now metal components can be produced using powder methods. A variety of new materials, including durable elastomers and flame retardant plastics, are being tested, which could create new opportunities for 3-D printed spare parts.

Instead of buying its own printers, Deutsche Bahn works with a network of service providers that produce the parts.

The defense sector is another area that has expressed a strong interest in additive manufacturing, Thiébault said.

“In France, we are working with the French Army, and the French Army last year bought 50 plastic printers — 50 FDM printers,” she said. “The goal is to deploy these 50 printers in different locations in France so that when an operator or when a technician breaks a part or needs a specific part, he can print directly the part.”

The French military is using 3-D printed replacement parts for vehicles, including headlight fairings and parts for hatches on light armored vehicles and armored infantry vehicles, and drones, among other things. In some cases, the military can use plastic 3-D printed parts in place of metal parts, she added.

Military units like to have plastic 3-D printers on hand to quickly replace parts that break, she said.

While the use of metal printers makes sense in some military settings, they require more expertise, qualified operators and specific storage conditions. “It is not always easy to ensure all these conditions in field operations,” Thiébault said.

“It makes sense to have metal 3D printers in OPEX [overseas operations of the French Military],” she said. “That requires expertise, qualified operators, specific storing conditions. It is not always easy to ensure all these conditions in field operations.”

3YourMind’s Agile Manufacturing Software Suite for 3-D printing includes three modules:

• Agile PLM, which manages the innovation process, including storing information about spare parts and analyzing those parts to determine which are a best fit for additive manufacturing;
• Agile ERP, which manages business processes, including ordering, pricing, payment, fulfilment and reporting between departments and companies;
• Agile MES, which manages production processes, including planning and optimizing resources, connecting printers, and aggregating and analyzing print and quality data.