Rather than offering an alternative, 3D printing can be the optimal way of producing precision components for collaborative robots, as demonstrated in the following case study from Markforged.
The challenge
Harvestance, a design and engineering services company, specialises in additive manufacturing. They provide 3D printing design solutions (DfAM) and services across various industries, including automotive, semiconductors, footwear and food tech. Harvestance received numerous inquiries for the design and manufacture of customised, lightweight and strong grippers for collaborative robots, aimed at automating production lines.
Traditional aluminum grippers, often heavy, limit the weight of workpieces that can be lifted and consume more energy. Harvestance’s customers, including collaborative robot users and robot system integrators, expressed several pain points:
- Collaborative robots are typically limited to small payloads of 20kg. Conventional aluminum grippers made by CNC machining usually weigh 1 to 2 kg or more limiting the weight of the work it can handle.
- Job site conditions vary, requiring customised grippers. However, the complexity of geometries and conditions makes customisation a challenge for traditional manufacturing.
- Pneumatic grippers with multiple suction cups require numerous vacuum tubes, potentially causing interference with robot movement.
- Designing custom grippers for each set of usage conditions posed a challenge in maintaining price competitiveness.
The solution
“We were convinced that 3D printing could fully address these pain points. We chose Markforged composite 3D printing technology to reduce the gripper’s weight while improving its strength and stiffness, optimising performance,” explains Harvestance CEO Seungjae Leem.
Harvestance focused first on lightweight design, integrating vacuum channels from the compressed air source to the suction cups directly into the gripper body, enabling one-touch fitting without external tubes. They adopted various design methodologies to enhance the quality and efficiency of 3D printed parts, such as redesigning to minimise surface roughness and creating self-supporting internal vacuum channels. This approach improved quality and reduced time and costs.
Part material is critical for factory production tools like grippers. Mr. Leem and his engineering team tested various printers and materials including Fused Filament Fabrication (FFF), Stereolithography (SLA), Selective Laser Sintering (SLS), and Powder Bed Fusion (PBF). Only Markforged, with Onyx and Carbon Fiber Reinforcement, could meet the flexural and impact strength these parts required for certification.
Another Markforged advantage is superior surface quality. All of the other 3D printers Harvestance evaluated required post processing steps, such as melting away support structures, depowdering, washing and curing, or polishing, whereas Markforged printed parts come off the print bed ready to use, without any delay or extra labour cost for post processing.
Harvestance turns to the Markforged FX20 when they need to print larger tools such as customised grippers for palletising and heavy pick and carry tools for large industrial robots. The faster FX20 also speeds up production 3 to 4 fold.
“Utilising Markforged 3D printing technology, we achieved an 80% weight reduction compared to standard commercial grippers and reduced delivery time from two weeks to two days, compared to conventional CNC machined grippers,” says Harvestance CEO Seungjae Leem.
By reinforcing the bottom of the gripper body with continuous carbon fiber and glass fiber, Harvestance created a strong, light gripper capable of supporting heavy workpieces without altering its shape.
“Markforged’s high-strength material (Onyx), Continuous Fiber Reinforcement, excellent surface finish, and easy post-processing have been ideal solutions for us. Our engineers can focus entirely on their work, developing products without concerns about mechanical properties, post-processing burden, or quality,” added Leem.
