3D printed spare parts – a potential risk?

What are the risks associated with 3D printed spare parts?

3D printing has been around for quite a while already but only in recent years has the technology developed and expanded into various new industrial areas.

3D printing

Spare parts management is an important and complicated element of the maintenance programmes of industrial companies.

Industrial machinery constitutes a long-term investment and may need to be maintained, repaired and updated for decades to come. Doing this cost effectively and reliably is a challenge.

The Digital Spare Parts Project by Aalto University and the VTT Technical Research Centre of Finland show how digitalisation and 3D printing provide opportunities to industries to streamline their business processes. However, the many changes also mean there is a possibility of new risks.

The basic idea of 3D printing was invented as early as the 1980s. It is also known as "additive manufacturing" as 3 dimensional objects are produced by adding material layer by layer from a printer.

The objects can be virtually any shape based on a digital data model. The technique is being applied to an increasingly broader range of areas from the production of spare parts, components, medical devices based on a patient’s own measurements, clothing, toys and pharmaceuticals up to large building materials. The technology has developed to support serious high-tech applications in the manufacturing industry, even in qualitycritical industries like the automotive and aerospace industry.

A digital file is created in computer-aided design (CAD) software and stored in a file format from which the 3D information can be sliced into hundreds or thousands of 2D layers. The printer understands the file and prints the slices as layers on top of each other and produces the three-dimensional object.

The materials used in 3D printing are mostly plastics, metals or ceramics. The chemical and physical characteristics of the materials and their bonds vary. The choice of materials has increased rapidly enabling ever wider applications. However, the amount and quality of materials suitable for processing through traditional manufacturing technologies such as forging and moulding are even greater.

Industrial spare parts

The maintenance of machinery requires systematic service and available spare parts. The Original Equipment Manufacturer (OEM) is the natural manufacturer and supplier of the parts. This means that production is centralised on site at the manufacturer. The client's urgent need to have a specific spare part at hand depends on the equipment and process. In just-intime conditions, even the slightest error or unexpected incident may disrupt operations and delay the availability of a spare part, consequently jeopardising the continuity of the operation.

To manage the risk, plant operators need to strike a balance between their own warehouse carrying a range of spare parts and the manufacturer’s ability to quickly supply the required parts. However, maintaining large spare part warehouses ties up capital and is counter-productive from a business perspective.

This is where the benefits of 3D printed parts enter the picture. They can be produced locally and quickly on site by the customer or on site by the maintenance service provider. Besides offering availability, the method also enables updated versions and other modifications. This requires, of course, the digital information for the design to be available.

Quality assurance

3D printing technology does not produce precisely similar materials to traditional methods. This does not mean that the spare parts wouldn’t be as durable as the original parts. But it is important to adapt quality control to ensure the product is suitable for its purpose.

Typically, the parts will also need postprocessing and there are numerous parameters that must be controlled to ensure quality. This is more challenging as there are currently no uniform qualitycontrol procedures. The lack of standardisation and possible certification poses further challenges.

Supply chain

The more parties in the supply chain, the more contractual relationships. Managing supply chain risks may involve dealing with the OEMs and manufacturers of printers and suitable raw materials, digital modelling, software, testing equipment, etc.


The manufacturer and seller of a spare part is liable if the part is defective and causes injuries to personnel or damage to property. Between commercial enterprises the liability is based on the sales contract. In the contract, the parties agree on the product specifications, delivery and consequences of any breach of contract such as a defect. The Sale of Goods legislation complements the sales contracts with default regula­tions if something has not been specifically agreed.

Usually, sellers are liable for direct damage without their own negligence and for consequential losses through negligence, but these can be freely agreed upon. When users of the part produce the part themselves, several liability issues arise. The user is the manufacturer so there is no seller. But what about the seller of a 3D printer? Again, it depends on the contract whether there is any liability. Very easily the damage caused by the products would be outside of the printer producer’s contractual liability as indirect damage.

A digital file may be developed in various ways from the original CAD file or by measuring or scanning the original part. There could be alternatives for the liable party. Other potential parties include the material manufacturers or sellers and the software providers. Contractual relationships form a wide and complex matrix. Quality control of the parts by the user may remain the essential safeguard against damage.

Liability for bodily injury caused by defective physical products is based on strict liability of the manufacturer according to Product Liability Law. This applies also to accidents caused by heavy machinery or their components at industrial sites. When producing parts through 3D printing, even this becomes complicated. Who the manufacturer is in the legal interpretation may be unclear.

IPRs, Cyber

There are risk issues that are not handled further here including the use of patents and other IPRs and cyber risks. Anything digital may be hacked one way or another.

Risk management programme

Spare parts are important to continuity of the operation. Their availability may dramatically impact downtime and risk of Business Interruption. Thus, an industrial company must have a sound risk management programme that addresses all factors that expose the company to machinery breakdowns and consequential business interruptions. This includes the management and supply of spare parts. The criticality of each part to the process should be assessed. Critical parts need to be available, which usually means they are stocked by the plant.

This can be achieved through VED classification – Vital, Essential and Desirable. It is important for vital parts to be available even if they would be improbable to wear out like the consumable parts such as bearings.

We see that spare parts management requires a complex balance between risks and costs. The availability and delivery times vary. Besides these issues, risk management may include follow-up of indicators in the use of machinery that anticipates future risks, thus giving more time to arrange parts to become available when needed.

Liability issues mean that there may not be any liable party to claim damages from in the event that the spare part does not fulfil its function or breaks. Managing liabilities means assessing contractual relationships and using contractual terms and specifications systematically.

Business Interruption

Property insurance for an industrial policy holder covers accidental physical loss, destruction or damage to insured property, which was not intended by the insured or could not have been foreseen by the exercise of reasonable care and skill on the part of the insured. Insurance coverage also supports any well-maintained property when 3D printed spare parts are used.

Naturally, there may be safety regulations or other requirements. However, in the standard terms, 3D printed parts do not receive special attention. The same applies to Business Interruption insurance. The coverage is tied to the insured events covered by the Property insurance.

Liability relations may be complex

As explained in this article, liability relations may be complex when industries start producing their own spare parts. But whenever there is liability, liability insurance is valid. Product liability policies offer protection to the manufacturer if 3D printers or raw materials are defective and cause damage or injury. General liability policies offer protection, for example, in the event of errors during assembly. Consultant’s liability covered by Professional Indemnity insurance may cover design errors.

Read also about the digital spare parts project. Risk Consulting has interviewed
senior scientist Sini Metsä-Kortelainen from VTT Technical Research Centre of Finland Ltd.

Article by

Matti Sjögren

Nordic Liability Risk Management Specialist, If