Have you ever been in the situation where you were working on a critical project, and mid-way through it you are faced with a problem that you don’t know how to solve? That’s exactly what happened to me during the design and iteration process of my “Origin One Ultimate Demo Part” (if you haven’t seen it yet, click here to check it out!). Luckily, I’ve been working with the Stratasys FDM technology daily for close to 10 years and given the advent of a new machine and a fantastic new material Nylon CF10, I was able to easily come up with the perfect solution and at a surprisingly low cost, 3D printed soft jaws!
The goal of my Origin One Demo Part project was to demonstrate the incredible properties that can be achieved using the Origin One and the Henkel LOCTITE 3D 3843 resin. With my first iteration printed I could see how everything looked and get initial dimensions to adjust accordingly and ensure that my bolts would fit into the part. I also used this version to test out my tapping skills and attempted to add some heat set inserts (this failed, as thermoset resins don’t melt like thermoplastic). During my first and second iterations, I employed the use of a bench vice to hold the part in place to tap two holes and apply the two inserts to it, but I quickly realized four things:
- The teeth on the vice jaws were leaving impressions on the outer surfaces of my part.
- The shape of my component is thicker in one area than another, so only the thicker area was being held in place when orienting the part for the top facing holes, and this caused issues with the part staying in place.
- While I could use the jaws of the vice to push the insert into the part, it was VERY hard to hold both the part and insert in place while tightening the vice until it made contact with both. Let’s just say I dropped both the insert and the part a handful of times, which was quite annoying!
- My small part was prone to falling out of the vice jaws the second I loosened them.
I continued iterating the design, adding some complexities such as knurling on the bottom, carbon fiber texture on the sidewall, and even a little frame for a QR code sticker. During that span of time, though, I kept thinking to myself that if I were going to print and assemble at least 50-100 copies of this part, I would need to solve all four of those problems to both make the process smoother, and also to end up with the best overall quality parts! That’s when it hit me…
The Right Tools for the Job
As I mentioned earlier, I’ve been using a variety of FDM printers from Stratasys for close to 10 years now to make quality parts and solve all sorts of problems, ranging from the uPrint, Fortus 250mc and 400mc, then to the newer larger machines: the Fortus 450mc and F900. Recently we added a new flagship printer to our Print Lab: the F370CR. What makes this new 3D printer so special? It’s a quiet and reliable office friendly printer that brings the consistency and repeatability of an industrial level additive manufacturing machine. It has a wide material capability including Composite Ready filaments made with chopped carbon fiber throughout. The F370CR is uniquely poised to solve my problem since it enables me to run Stratasys’ newest material, Nylon CF10.
What is Nylon CF10?
This filament is a combination Nylon blend base material and 10% chopped carbon fiber by weight. Some printers out there right now can embed a bit of carbon fiber into parts in select areas to increase rigidity of the component only in those specific areas (which only increases the rigidity of those parts on the x/y plane); Stratasys Nylon CF10’s even distribution of carbon fibers means that your ENTIRE part is comprised of those carbon fibers, and the mechanical properties are improved on the Z axis as well! The result is a filament that has extra strength, stiffness, durability, and chemical resistance, making it a fantastic option for end use components from the machine shop floor to the design engineer’s office for testing new prototypes.
Another neat thing about the Nylon CF10 material is that it can run on both the F370CR and the F190CR (a bit smaller, lower cost machine). Nylon CF10 prints using the fully chemistry soluble QSR SR-35 support materials. Nearly all of the popular carbon fiber printers on the market are stuck in the low end hobbyist range and use their own model material as support, leading to a ton of time spent meticulously removing very difficult to remove supports. The Stratasys QSR support material dissolves off quickly and easily, requiring no additional labor time other than the ten seconds it takes to pop your part off of the tray and toss it into the wash tank! No labor costs due to support removal, no scrap rate due to damaged parts (which is traditionally due to chisels or plyers going astray during the support removal process of other popular printers out there), and no design limitations due to complex geometry are some of the top reasons to use the Stratasys Composite Ready F series machines!
I’ve been learning more and more about the new Nylon CF10 material for a few months now, and while some of the top applications for it are factory ready End-of-Arm Tools, Drill Guides, Machining Jigs, Press Brake Tools & Dies, and durable assembly fixtures, this material is also fantastic for industrial 3D printed soft jaws used directly on the machine shop floor. My soft jaw parts are going to have to hold up over time being clamped tightly as I add my inserts to my Henkel LOCTITE 3D 3843 sample part and not damage the surface appearance of my parts during the process.
Why did I create two sets of jaws? My 3843 demonstration part has three holes that run parallel to the print head of the Origin One, and another three holes that run perpendicular to it, but the geometry is not perfectly symmetrical. As a result, I need one set of jaws to hold my part in the vertical orientation, and another set to hold it in the horizontal orientation.
Once I had that eureka moment, I got to work! Using SOLIDWORKS, I took my Origin One Demo part into an assembly, simplified it down to just the flat surfaces and a few of the holes, built a block around it, and then used the “Cavity and Core” features to subtract the demo part from what would become my jaws. One of the more interesting features of the design are two mirrored alignment features; each part has a male and a female component, which allow me to pseudo assemble the demo part + inserts inside of the jaws before closing them in the vice. They also keep everything perfectly aligned during the process, and they were very easy to print!
The trickiest portion at this phase was regarding how I would best force the insert into the 3843 demo part. My initial design had a mound and a peg for the insert to slot into with the hopes of using the jaws themselves to force the insert in. But, after spending about 10 minutes thinking about it, I figured it wouldn’t hurt to make a second iteration that instead had a slightly oversized hex slot, as this would enable me to thread my bolt into the insert and use the larger surface area of the hex bolt head to push the insert into the demo part. Honestly, there was no downside here; the Nylon CF10 material prints very quickly and is surprisingly low cost given its incredible mechanical properties, so adding another set of test prints to the build was a no-brainer!
One or Two More Small Problems…
The first two iterations of soft jaws worked GREAT! While I liked the ones that had the hex slot for the bolt head better, both versions worked without any issues right out of the printer. But, there was a minor issue with my design; in all of my excitement to solve problems #1-3, I had forgotten all about problem #4; the demo part AND the soft jaws still fell straight out of the vice once I loosened it back up.
I needed to design something that both the horizontal and vertical soft jaws could sit on, that would also fit directly over the jaws of the bench vice; a universal soft jaw adapter. Once that realization hit me, my coworker grabbed all of the measurements of the bench vice that I needed, and I had the adapter whipped up as a new assembly in SOLIDWORKS within about 10 minutes. What is even cooler is that even though I was out of the office due to a positive Covid test, I was able to send the job straight from my laptop at home over the encrypted secured cloud server connection straight to my printer in the office, and my coworker was able to press play on the build literally one minute after I had the design figured out!
The 3D Printing Data
I generally like to provide a bit of insight into what it takes to make most of my projects, so in this case it can be broken down into three sections: the Horizontal Jaws, the Vertical Jaws, and the Universal Vice Adapter. For reference, we printed all of these parts with a completely solid infill density at 0.013” layer height, which is both our fastest printing and strongest resolution for layer to layer adhesion. The data provided is for the hex slot variant, as I settled on that being the best option after testing.
Vertical Soft Jaws
This set of jaws took a combined 6.017 cubic inches of Nylon CF10 model material, 0.625 cubic inches of QSR support, coming in at a total cost of $36.94 of material used, and took 2 hours and 14 minutes to print. An interesting bonus for the jaws is that in order to obtain the best possible part strength, the internal cavity features were printed face up, parallel with the build tray, so the ONLY support used was right along the base of the part. As a result, the jaws popped right off of the tray and required no wash tank time to dissolve them!
Horizontal Soft Jaws
This set of jaws took a combined 5.949 cubic inches of model material, 0.626 cubic inches of support, coming in at a total cost of $36.55 of material used, and took 2 hours and 13 minutes to print. Similar to the Vertical Jaws, these ones only had support on the base, so they popped right off with no wash tank time needed; the parts were ready to use within one minute of the printer completing the job!
Two Copies of the Universal Vice Jaw Adapter
The way that these were built, there was a pocket of support under the primary compression surface of the adapter, as it was designed to lock into the existing shape of the bench vice jaws. As a result, they used a combined 5.244 cubic inches of Nylon CF10 and 2.313 cubic inches of QSR Support, coming in at $38.38 for the pair, and took a combined 3 hours and 9 minutes to print. Wash tank time took roughly 2 hours after the parts finished printing, followed by a quick rinse and air dry, so these parts printed overnight and after going into the wash tank first thing in the morning, were ready to use just before lunch.
In the end, the F370CR saved the day! It was the right tool for the job, helping me to quickly, easily, and affordably produce durable Nylon CF10 parts that are going to last a TON of uses. Having this kind of additive manufacturing power at your fingertips is a real game changer. I was able to use my programs remotely and send the prints directly to the printer to ensure that there was no delay in the project lead time. We stayed on track with our schedule and will have the demo parts to our team in no time!