In mass manufacturing, 3D printing is more often used as an enabling technology rather than a means to create finished products. In a recent survey conducted by Dimensional Research, 74% of manufacturers said they currently use 3D printing for manufacturing aids and tooling jigs.
Additive manufacturing is used to create lightweight and durable jigs and fixtures that securely hold tools or unfinished parts in place during the manufacturing process, making it easier for machines, robots, and workers to do their jobs better.
In the case of large jigs and fixtures, traditional methods often involve assembling multiple printed parts, resulting in time-consuming and labor-intensive processes. However, there is a growing interest in exploring large-scale 3D printing to overcome these challenges. High-speed extrusion technology makes it possible to produce these tools as single, integrated pieces directly on the factory floor. This approach reduces the need for post-printing assembly, leading to substantial time and cost savings.
Speed is vital in mass manufacturing operations as it directly affects production volume and cost efficiency. Regarding large 3D-printed jigs and fixtures, speed is crucial to ensure the final parts possess the required strength and durability. High-speed extrusion technology enables precise and rapid movement of the print head, allowing for the deposition of filament at high speeds with exceptional accuracy. This results in superior layer-to-layer adhesion and eliminates issues like delamination, ensuring that the printed parts meet the necessary performance standards.
Large jigs and fixtures find applications across various manufacturing processes, such as securely holding raw materials during laser etching, polishing, milling, or finishing treatments. They may also be used for shaping and imprinting large plastic sheets, furniture routing, or automotive painting. These tools serve workers and automated assembly lines, and their size sets them apart from smaller jigs and fixtures.
Advantages of 3D Printing Large Tools as Single-Piece Creations
The advantages of 3D printing large tools as a single piece are numerous. It allows for faster production, reduces labor requirements by minimizing post-finishing and assembly, and enhances the overall strength and integrity of the parts. Additionally, 3D printing enables the creation of complex designs that would be challenging to achieve with traditional subtractive manufacturing methods.
Plus, in an open-ecosystem approach to 3D printing, engineers are free to design jigs and fixtures to their exacting specifications using a wide variety of extrusion materials from any supplier and output anything from one machine. Think about a 600 mm-tall “Y” shaped fixture with the tips of the “Y” spaced 450 mm apart, used to hold large circular steel and glass plates for etching. The three prongs can be printed in one piece using high-temperature nylons for strength and rigidity, while the three grippers, each 300 mm long, can be printed from non-marring TPU on the same machine.
Expert Guidance for 3D Printing Large Jigs and Fixtures
Here is some general guidance for material selection and best practices to ensure your 3D-printed jigs and fixtures are the best they can be.
Effective CAD Design
Engineers should consider several best practices to optimize the CAD design phase of 3D printing large jigs and fixtures:
- Ergonomics is crucial in ensuring the design allows for one-handed use, leaving the other hand free for measuring or using another tool.
- Incorporating release mechanisms facilitates easy removal of the part from the fixture after use, enabling a smooth transition to the next assembly step.
- Curved surfaces and recessed channels should be incorporated into the design to facilitate easy cleaning, as hard corners can make it difficult to remove debris that could affect the positioning of the next part.
- Leaving space around drill holes is necessary to account for burr creation, allowing waste to fall away without interfering with accuracy or visibility to the tooling point.
- Implementing the concept of Poka-yoke, which involves incorporating incorrect geometries and odd dimensions into the design, helps identify placement insertion errors, reducing the chances of mistakes.
- Building connecting locators into the design ensure precise seating and alignment, guaranteeing assembly in the proper orientation or enabling easy mating of two parts.
- Integrating datum points eliminates the need for secondary stamping or engraving, making inspection easier or allowing for the printing of important data on each part for inventory and identification purposes.
- Using electrostatic discharge safe (ESD) materials is crucial for specific applications such as surface mount technology and circuit board production, as they prevent sparking during electronics assembly.
- Additionally, incorporating hard tooling points, such as heated metal shafts and inserts, enhances accuracy and durability, particularly in drill guides for precise drilling.
Best Practices for Successful 3D Printing
During the 3D printing phase, it is advisable to streamline the material selection process by narrowing the options to a subset of four or five materials that offer the necessary properties for the fixture.
Properly drying polymers before use is essential to avoid structural weaknesses caused by excess moisture in filaments.
Testing material compatibility with the end-use environment ensures the filament’s resistance to known chemicals and solvents, preventing degradation or compromised functionality.
Incorporating a small amount of carbon fiber into the material mix is recommended for additional strength. Reinforcing the fixture with ribs or extra material can enhance its strength without significantly impacting build time or cost per part.
Part Validation is Critical
In the final phase of part validation, measuring critical dimensions against the CAD model and the 3D printing file using tools like micrometers or calipers is crucial. Checking for a snug fit confirms proper alignment and positioning of the part within the fixture. Evaluating excessive clamping force ensures that the pressure exerted by the jig or fixture does not damage the part or alter its dimensions.
Creating the Unsung Heroes of the Factory Floor
Jigs and fixtures are the unsung heroes of the factory floor. They enable the consistency and repeatability needed to achieve mass production, guiding people and robots through precise manufacturing and assembly operations.
Adopting large-scale 3D printing for jigs and fixtures offers manufacturers streamlined production processes, reduced labor costs, and enhanced part performance, contributing to improved efficiency and productivity in the industry.
Author: Garrett Harmon, Application Engineering Manager at Essentium.