Here at TriMech’s Connecticut office, we had been printing in 17-4 stainless steel using the Desktop Metal Studio Printer beta unit, but in December of 2018, we installed the complete Desktop Metal Studio System! Having the debinder and furnace in-house has really helped us speed up design time on our prototype sample parts.
Now, it’s time to unveil our first official TriMech branded sample part in 17-4 stainless steel from the Studio System, a metal bottle opener.
Why a Bottle Opener?
We’ve designed and printed quite a few parts from scratch over the past year to show what the Studio System is capable of. So, why the bottle opener? First, the part strength required to pop off a bottle cap isn’t small. While we can make plastic bottle openers, they may eventually break with repeated use, however, a 17-4 stainless steel one should never break. Second, we wanted to print an item that would help us show what this exciting new additive technology can do, therefore we chose a piece that is difficult to machine and to which we could add nice design features. Finally, since it’s small enough to fit onto a key chain, it seemed like a great low-cost sample part to make.
For my design, I wanted to make a part that would be as strong as possible, so people could use it for years with minimal wear and tear, while also including some neat eye-catching design elements. At the same time, I wanted to make sure that we reduced metal usage where possible to end up with a reasonably low total cost per part.
The shape of the part includes bottle and can opening features, a large flat surface on the can opener sidewall for the TriMech logo, a key chain loop and an artistic spiral design below the bottom tooth of the opener. This spiral feature consists of six 1.4mm teeth, which sweep with a 60° spiral. While we can safely print a steeper, self-supporting angle I prefer the aesthetical quality because each tooth ends directly below the other. The lower tooth on the bottle side will also see the most stress in use, so this feature helps save on material usage while increasing the overall part strength.
Reducing Cost Per Part
With the goal of being able to produce large batches of these bottle openers as sample parts, I minimized material usage by shelling the part. I used a partial cut-extrude offset 1mm from the outer edges of the part 2mm deep with a draft positive angle that would look neat and not require support to build. A through-all cut on the resulting flat surfaces helped lower the costs and increase part strength by using less material overall and ensuring that there are more contours being used instead of semi-sparse infill where it matters the most. Additionally, I chamfered the lettering on the logo on all edges so that it wouldn’t require any supports, which created a uniform surface finish on all sides of the letters.
I slapped some fillets around the part to smooth down most of the edges so it won’t get stuck in your pocket. After that, I was done!
Using the Desktop Metal Studio System
With the part ready to go, we used the Desktop Metal Fabricate Software to send the job to the Studio Printer, debinder and furnace. This is a cloud-based software that is accessible from any internet-connected computer in your company with a login.
Running the printer is incredibly straightforward; insert a build sheet, pull up the job on the touchscreen, make sure that you have enough metal and ceramic interface loaded to complete the job and press print!
Once the print was completed, it was time to run the parts through the debinder. This machine uses a proprietary blend of fluid to remove the wax binder from the parts, which then leaves them as a combination of metal and a polymer binder.
Once the parts came out of the debinder, we then used the furnace to sinter the parts, which removes the polymer binder from the part during the heat up time and fuses the remaining metal particles together to create the final all-metal part.
The furnace’s process is fully automated, and slowly will ramp up to roughly 1300° C, during which time the polymer binder is removed from the part, remain at sintering temperature for a period of time and then slowly cool down to ensure that the parts aren’t damaged from cooling too quickly. This can take 24-48 hours to complete depending on the average mass and number of parts in your job.
When the cycle was completed, the chamber temperature was still around 200° C, so I wore gloves when I removed the retort rings and parts. Those parts are now fully sintered metal and are either ready for machining or immediate use. In this case, I used a belt and disk sander to smooth down the top, bottom and lettering to get a nice contrast of glossy vs. matte surface finish that really makes those areas stand out.
Takeaways from Printing with the Desktop Metal Studio System
Creating genuine 17-4 stainless steel parts on the Desktop Metal Studio System is a breeze! The entire process is very straightforward, and the Fabricate and touchscreen software on each machine do a great job of guiding you through this process, taking out all the guesswork of running the machines. When parts come out of the furnace they’re ready to go as actual usable 17-4 stainless steel parts, and if you want to apply some post-sintering cleanup process to them you can, but they’re great right out of the furnace too!
Want to know more about the complete process of designing and creating the sample key chain shown above? Download our guide.