3D Printing offers a great resource for quickly and affordably creating end of arm tooling for the many tasks that collaborative robots take on.
Collaborative robots are a great resource for smaller companies looking to automate. They are a flexible resource for completing repetitive tasks in assembly and sorting because of their flexibility and ease of training. The trouble is that robot grippers are not very versatile. Often each task needs its own specialty gripper to be created to grasp the objects in that task.
Creating these grippers is both expensive and difficult due to CAD requirements and machining costs. 3D Printing makes the creation of EOAT much easier and flexible.
End of Arm Tooling Created with 3D Printing
3D Printing is a very flexible means of manufacturing EOAT. It allows users to very quickly create custom fingers or parts nests without many machining concerns or time input. That is why Schunk has started providing resources to create custom 3D Printed end effectors. EMI has also started selling 3D Printed EOAT solutions. And there is the Slant 3D Part Mason Project that provides customisable Grippers for Collaborative robots.
Since there are so few design constraints on 3D printed parts you also don't have to worry about high costs of engineering and design bottlenecks.
How to get 3D Printed EOAT
Get a Model
At Slant 3D we maintains a team of 3D modelers that can help you design a gripper for your application within hours or days. You can also access pre-made 3D models for gripper fingers and pads at Part Mason. The models are ready immediately to be printed by a service or on your in-house 3D printer.
One other option is to use online resources such as eGrip by Schunk which can generate .STEP files that can be 3D Printed very affordably.
Print the Part
Once you have the model you can print it on your In-house 3D printed, such as the Mason. If you need higher volumes of the part to outfit an assembly line, or if you need specific material properties you can submit the design for a quote. Generally it only requires 2-4 days to turn around 100 pieces at Slant 3D.
Use Your Robot
When the parts arrive they can immediately be mounted onto your collaborative robot and put to work. If you ever need more pieces they can be ordered instantly without redesign or setup.
High Volume 3D Printing allows companies to produce products at any scale without the cost of tooling. For new companies and products this eliminates the high initial cost of tooling. And for companies making complex hardware, or low volumes of products 3D printing can allow them to access new markets faster and with far less risk.
So how is high volume 3D printing able to replace injection molding. There are a number of ways. Fast 3D printers or Lots of 3D Printers.
Fast 3D Printing
Fast 3D Printers are systems that are able to adiditvely produce parts very quickly. These are systems like HP Multi-jet Fusion (MJF) or Carbon's Digital Light Synthesis (DLS).
These technologies are able to produce parts very quickly with 3D printing. But they are limited in geometry and require a lot of post processing, so they remain quite expensive. Though when compared to the high up front cost of molding, these processes can be very useful in high margin products. The design freedom they offer with lattices and light-weighting are also big advantages.
Lots of 3D Printers (or 3D Printing Farms)
3D Printing Farms, like the ones created at Slant 3D, used hundreds or thousands of 3D printers all working in parallel to create parts very quickly at scale. A single part may take an hour to produce, but with hundreds of machines working on that part, you are now making hundreds of parts per hour.
3D Printing farms are able to achieve a much greater scale and a much better cost advantage than other systems because they take advantage of scale. They source larger amounts of more common materials and high automation eliminates the labor costs that can make other processes very expensive.
While fast 3D printing systems may only be affordable compared to molding up to about 1000 parts, 3D Printing farms have achieved cost parity with molding up to 100,000 parts. And that is just by eliminating the need for molds. Long term the savings can be even greater with better supply chain management that 3D Printing allows.
Choose the Process for your Product
It is important to understand that each manufacturing process is not a perfect substitute for any other. Each has its strengths and weaknesses. As you plan your product consider everything from design attributes to ultimate scale and production needs.
High volume 3D printing is great for getting started and scaling up. It also can provide many interesting engineering advantages. Injection molding, is great at high volumes and also provides certain engineering advantages. It is all a matter of what you product needs to be when it gets into customer's hands and your budget for making that happen.
3D Printing is an ideal means of manufacturing custom electrical enclosures.
We have worked with many industrial clients that have utilized our large format 3D printing capacity to produce electrical enclosures. The reason they prefer 3D printing is to traditional machining is primarily based on cost.
The additive nature of 3D printing reduces the amount of material needed to create an enclosure when compared to subtractive machining. After all a delrin block is far more expensive than a kilogram of ABS. Injection molding is not an option because with larger enclosures, greater than 12 inches cubed, the cost of the mold is very prohibitive. Not to mention the time to have just 10-20 enclosures produced is too long. But 3D printing can produce the pieces in 1-2 weeks.
But as is the problem with most items submitted for 3D printing, the engineer of the enclosure does not design for 3D printing. They take a traditional enclosure and expect 3D printing to create a result that is identical to other processes. It will not be. So we wanted to compile some tips for designing electrical enclosures.
Design a Foundation Layer
When printing any part a decision must be made about what side of the part will be against the print bed. Traditionally this will be the largest single flat surface. This is used to have maximum bed adhesion which limits warping and failure of parts. Generally this side is the back or bottom of the enclosure that might be mounted against a wall.
Ideally this side should have no complex features such as text. Just holes. If there is text, they it can become unreadable as the first layer is often "squashed" in order to help with adhesion.
When designing your enclosure try to create a large simple side which can serve as the foundation
If all side of an enclosure require critical details there are multiple solutions.
Printing the part with the open face down will require a longer set-up period. This orientation is difficult tp print reliably. It also requires that the enclosure be printed with support material throughout. This results in a rough interior texture and more expense, due to the support material. There is also the risk of any interior bosses or features losing detail because they printed on support material. You can see a comparison of sections of the same part printed open side down and up in the photos below.
Infill or Ribs
When a part is 3D printed there is the ability to either create a solid piece or reduce the density of thick areas of the part by using internal lattices. This "infill" reduces print time and material used and is highly recommended.
The infill makes the part behave like a sandwiched composite. So even though it uses less material it is structurally very strong at low infill percentages of less than 50%.
However if more structure is required we recommend adding ribs. These are simple to print and provide a large amount of strength. Using ribs with thin walled enclosures are ideal as they result in even less material used than infill and better control the structure of the enclosure.
Since electrical enclosures are generally purely functional, they are often printed at the lowest resolution possible. The layering is visible, but it reduces lead time and has not structural downside.
If a more refined surface is necessary the layering can be be made to nearly disappear with high resolution printing. The downside is that the printing time per part can go up as much as 300%. And the smooth surface can only be created on straight vertical surfaces. Any sort of incline or vertical curve will make the layering more visible. All of this is well defined in the part below, where it was printed with high resolution.
Reduce Rims and Overhangs
It is very common to create a rim around the top of an enclosure or case. This improves rigidity for a lid or for ejection from a mold. These rims often protrude some distance horizontally from the part with little filleting below them. This is done to reduce material used, but that is unnecessary for 3D printing (infill eliminates excess material from thick areas).
These rims in fact increase the cost and difficulty in manufacturing the part with 3D printing, because they must be supported. In the case of the part above an entire secondary structure of support material from the base of the case to the rim must be built simply to support the rim in the last 0.25 inches of the part. This adds a great amount of print time and material, therefore increasing the cost of the part.
The way to avoid this is simple to add a chamfer of fillet underneath the rim, so that it seems to gradually protrude from the case as it is grown layer by layer. Examples of this filleting are shown below.
In this particular case, the enclosure actually has an overhang angle of 90 degrees, thus requiring support. If a 45 degree chamber was adding it would greatly reduce the cost of the part.
Hopefully these pointers will help you when working on your next enclosure. When working with Slant 3D one of our engineers is always available to help you through the process. And when you submit a design for quotation we will always be willing to make recommendations in order to reduce cost.
3D Printing is a very viable manufacturing option for electrical enclosures. But to use the process effectively you must design for it. Pressing an part designed for injection molding into a 3D printer will never created an injection molded part. Better to design a part for 3D printing.