HP Multi Jet Fusion: how 3D printing can help in industrial automation

Robotic arms and automated production lines are now capable of handling increasingly complex tasks. However, the robot itself is only part of the overall solution. Equally important is the tool at the end of its arm – for example, a gripper used to grasp components, or a fixture that holds them in the required position during production.

Such tools often consist of aluminium profiles, machined parts and a range of standard components. Their manufacture is usually time-consuming, and any modification to the design therefore means additional work and time. Furthermore, if the tool needs to be adapted to a specific product or production line, the traditional approach may not always be the quickest or most cost-effective.

One solution is manufacturing using HP Multi Jet Fusion (MJF) technology. This enables the printing of functional plastic parts made from PA 12 engineering polyamide directly from a digital design. A designer can, for example, design a gripper with fewer components or adapt its shape to a specific application.

Where 3D printing can transform the design of a robotic gripper

A gripper is used to grasp and move products or parts thereof. Depending on the specific application, it may take the form of a simple tool or a more complex assembly featuring pneumatic lines, connectors, suction cups or magnets. It is one of the tools mounted at the end of a robotic arm, collectively referred to as end-of-arm tooling (EOAT).

The design of the gripper depends on what the robot is to grasp and how it needs to manipulate the part in question. The design therefore often consists of a combination of separate components that perform individual functions. This approach is tried and tested, but as the number of components increases, so do the number of joints, and consequently the number of assembly steps and maintenance requirements. Any change to the product or work process may then necessitate modification of the entire tool.

HP Multi Jet Fusion allows for a different approach to design. Instead of simply replacing metal parts with plastic ones, the entire gripper can be redesigned with the capabilities of 3D printing in mind. Some functions can be combined into a single part, its shape adapted to the component being gripped, or a lightweight design created where less material is required.

Why HP Multi Jet Fusion and PA 12 material

HP Multi Jet Fusion is a 3D printing technology in which parts are created by gradually fusing polymer powder. Production takes place in thin layers. First, a layer of powder is applied to the build plate, and the print head applies special activators to it, which determine where the material will fuse under the influence of heat. The same process is repeated until the entire part is formed.

Engineering plastics, such as polyamide PA 12, are used for printing functional industrial components. This material is also suitable for parts that are not merely intended as visual prototypes, but are designed to fulfil a specific function in actual operation.

One of the main advantages of MJF technology is design freedom. The design does not need to take into account the limitations of machining from a metal blank or the requirements for assembly from a large number of separate parts. And, where the application allows, certain elements and functions can be integrated directly into a single component.

This allows the designer to better adapt the part’s geometry to its specific purpose and to design shapes that would be more difficult to produce using conventional manufacturing processes. As MJF manufacturing does not require mould preparation, this technology is also suitable for single parts and small batches, where the cost of a mould would not be economically viable.

Continental: a robotic gripper more than 85 per cent lighter

An interesting example of MJF in use can be found at Continental Automotive Spain. When automating the assembly of automotive interior parts, the company had to address, amongst other things, the complexity and weight of the robotic grippers used.

The original solution consisted of a large number of components. These included, for example, wiring, connectors, magnets and other elements required to grip and handle individual parts. Such an assembly was not only heavy but also required ongoing maintenance and adjustment. Its installation and adaptation to the new workflow were also time-consuming.

The organisation IAM 3D Hub took on the task of designing the new solution, developing a new gripper and associated tools for Continental using HP Multi Jet Fusion. Rather than simply replacing individual metal components with plastic ones, it focused on a complete redesign of the structure.

The result was a gripper more than 85 per cent lighter than the original solution, whose reduced weight and inertia allow it to be used even on robotic arms with a lower payload capacity. The new design is suitable for collaborative robots, standard six-axis robotic arms and gantry systems.

Sodecia: you don’t have to wait a month for the new gripper

Sodecia, a global supplier to the automotive industry, was tackling a different problem. It needed to reduce the time it took to procure a new robotic gripper for handling car parts.

The original gripper had a modular aluminium structure supplied by an external manufacturer. The delivery time was approximately 30 days. This not only prolonged the process of acquiring the new tool, but also delayed the implementation of any necessary design modifications.

Sodecia therefore, in collaboration with HP’s application team, redesigned the original structure for production using Multi Jet Fusion technology. The new gripper was created from HP 3D High Reusability PA 12 material on an HP Jet Fusion 5200 system.

During the design phase, it was important to maintain sufficient rigidity for the specific task. The resulting solution is modular, allowing for easier adjustment and quick replacement of individual gripper parts. Thanks to the change in the manufacturing process, the lead time was reduced from approximately 30 days to less than two weeks.

Furthermore, thanks to MJF manufacturing, the grippers can be printed directly in Canada, without the need to import them from an external supplier. Sodecia thus saves not only time but also import duties, which would otherwise account for approximately 5 per cent of the costs, or roughly $1,000.

Gimatic: from prototype to bespoke robotic fingers

The fact that Multi Jet Fusion technology need not be confined to prototyping is also demonstrated by the Italian company Gimatic, which specialises in automation and gripping systems.

Initially, it used 3D printing primarily in the early stages of development. Gradually, however, it began to explore ways of incorporating the technology into the production of functional components, production jigs and final parts. In 2017, it therefore acquired an HP Jet Fusion 4200 system utilising Multi Jet Fusion technology.

One of the results of this expansion is bespoke robotic fingers and other end-effectors. Thanks to 3D printing, Gimatic can tailor their design to a specific product or the requirements of a given production line. Furthermore, it can produce functional prototypes within a few days. Selected parts can be printed overnight and dispatched the very next day after an order is placed.

Multi Jet Fusion technology is particularly cost-effective for single units and small batches, where conventional manufacturing or injection moulding might not be economically viable. However, Gimatic has not ruled out injection moulding from its production process – it continues to manufacture a large proportion of its parts using traditional methods. It utilises this technology where it enables it to deliver parts more quickly or offer customers bespoke solutions.

When is 3D printing worthwhile, and when is conventional manufacturing still the better option?

HP Multi Jet Fusion is not a universal substitute for machining or plastic injection moulding. Every manufacturing technology has its place, and the decisive factors are, above all, the specific application, the required part properties and the batch size.

For large and repetitive production runs, injection moulding is generally more cost-effective. When thousands of identical components are being produced, the investment in a mould is spread across a large number of units. Similarly, machining has its advantages for parts with high precision requirements, specific material properties, or where a metal structure is essential.

MJF, on the other hand, makes particular sense in situations where you need to:

• to make a robotic gripper or other end-effector lighter,
• to combine multiple components into a simpler design,
• to produce bespoke robotic fingers tailored to a specific product,
• to quickly produce a functional prototype or an alternative design,
• to manufacture single units and small batches without investing in a mould,
• to reduce waiting times for replacement or newly designed parts.

When making a decision, however, it is not advisable to focus solely on the price of a single printed part. With robotic end-effectors, factors such as lower weight, simpler assembly or quicker replacement when changing the production process can also play a significant role. All of this can have an impact on the operating costs of the entire production facility.

Start with the tool you’re already using

If you have your own design department and work with CAD data, you don’t need to start from scratch. The first step could be to assess one of your existing grippers, robotic fingers or production jigs. It is often in these that you can find scope for making the design lighter or simpler.

With MJF technology, it is important to consider the possibilities of additive manufacturing right from the design stage. It is not enough simply to take the original aluminium part and print a copy of it in PA 12. The best results are achieved when the design is adapted to the properties of the material and the manufacturing process.

3Dees is HP’s partner for industrial 3D printing in the Czech Republic and Slovakia. It helps companies assess the suitability of a specific application, select the appropriate technology and develop a solution from the initial design right through to the finished part.

Are you considering whether some of your robotic grippers or jigs could be manufactured using HP Multi Jet Fusion? Send us your CAD model or describe the specific application. Together, we’ll assess whether this technology is suitable for it.