Markforged printers which one?

Please post from real first hand experience.

How beneficial is the continuous fiberglass strand in the Onyx Pro or the other continuous strands offered in the Mark 2 compared the the plain ole Onyx one?

1 Like

I wish we had enough money to be asking this question… like I’m probably too broke to legally be on this thread

8 Likes

Me too and even with what money its questionable if it would be a wise decision. If I had the money for one. I’d probably buy a bunch of others with it. But it depends probably what you are going to print. We want to eventually print the whole robot. So build volume is critical. The MF ones with the laid in CF are very strong in the layer direction but layer adhesion is less than regular Nylon as if you add anything , chopped fibers, complete fibers, sometimes pigment it does not help. So right now we got a prusa clone prints Nylon great (with a garolite plate) cost us about 1500 with all the dodats that go around it like filament dryers, tools, enclosure etc. Our next one if we can come up with about 1200 to 1500 is going to be something like a CR-10 S5 that will be upgraded with a 750 W heated bed hopefully a garolite or PEI surface, Volcano hotend better Extruder and an enclosure and its own filament dryer. Then we could print up to 500x500x500 parts relatively Quickly out of most materials that are within budget. Now with the MF printers especially the continuous fiber ones you are locked into their filament. With the others I can use $10-12 HIPS, ABS for some structural stuff and check fit. And 910 and Bridge and CX12 are good Nylons and they are $80, $40, $50 ish a kg. For misc projects we went through about 40kg of filament in this school year so far which cost us about $700 so far. With MF that would be more than 10x that.

We used our onyx one extensively during the 2019, and are using it a lot more this off-season. We we’re so happy with it’s performance we ordered a second one.

I can’t speak to the value of continuous fiber as we only have a One; what I can say is that we didn’t come across any parts we felt would have really had a big benefit from having continuous fiber, and we printed a lot of unique stuff this year, a number of which was under a good amount of load.

3 Likes

One limitation that 299 ran into a couple years ago when using a local MF with continuous fiber inlay was that there is a minimum radius for laying the CF. Smaller features like gear teeth won’t benefit from the continuous inlay.

There’s a steep discount for being an FRC team which brings a Mark 1 down to less than half the cost of a regional registration and a Mark 2 comparable to 2 regionals of registration fees (or less than our trip costs costs to attend a second regional in a season.)

They’re not cheap printers but definitely within reach for a lot of teams, especially if this thread is saying Onyx is enough.

https://markforged.com/sponsorship/

3 Likes

For a non logistics person can you translate the costs?

I use a Mark 2 at work. We have had it for a while and it is a great printer. We got it for making end of arm tooling for robots. We make a lot of what I call gripper fingers. We were making these out of alum and they are about 0.25 - 0.375 square and range from 3-4 inches long. For these fingers we always use the CF inlay to make it stiff enough for what we need. The Onyx alone is very good however on these smaller/ thinner type parts you need the CF to keep it from flexing.

So how does this relate to FRC. 99% of everything I print for our robots are Onyx only. I did print a large sprocket for 35 chain that I put CF into. I don’t remember the size off hand but I had to print it in two pieces to get it to fit on the printer so I would think it was 7-8 inches in diameter. The main reason I put CF in it was to keep it strong and keep it from flexing. Like was said above you do have a min radius that kept it from getting the CF up in the teeth. It worked great for what we needed at the time. Everything else I have done has been Onyx only. I think these printers are perfect for the work we are doing and are worth the money. If I was buying for my team I would just get the Onyx printer. If you have money go for the others great but most can be done with Onyx only. I think in the next 3-5 years these will be as common in FRC as CNC routers.

1 Like

From my experience, the continuous carbon is nice but rarely useful in FRC applications if you have a CNC router or mill. I did some testing a while back and found the parts that would make good use of the continuous carbon strands where better off being made as aluminum (gearbox plates, billet bearing blocks etc.) and where slower to produce, more expensive and not much lighter than there aluminum counterparts.

The biggest upside to the continuous carbon for me was the ability to not have to think about the nylon absorbing moisture and loosing rigidity over time.This issue is easily rectified by adding a bit more material around the profile of the part but is something that does not come to mind if you are used to designing parts for traditional FDM printers.

I can also echo Anand’s statement that a lot of the smaller parts where it would be nice to use continuous carbon like gear teeth, extension arm bearing blocks, locking tabs/ latches etc. generally are either too thin walled or too small for continuous carbon to be added.

The one part i did find it useful for was in situations where you needed to thread into the part. there having continuous carbon was usually addable and helped prevent the issues highlighted in this video with the material around the threads failing. Threaded inserts generally address this problem well enough to not justify the Mark Two for FRC purposes.

My theory was that if they wanted to publish the sponsorship pricing, they would have. That’s the pricing I was presented with too. The Onyx One was also available on a similar discount.

The only other critical detail was we had to complete the purchase within 60 days of applying for the sponsorship.

A regional is $4-5000.

We used the onyx one this season and it’s handled pretty much anything we’ve thrown at it. I don’t see much use for the continuous fibers in FRC like most people have mentioned in this thread.

Oddly enough, the pure onyx teeth held up pretty well. I’d do a pulley these days to better distribute load but we were pleasantly surprised to find that the pure onyx swerve gears geld up through a bunch of rough driving during demos.

1 Like

Were these 20dp gears?

Yup.

I tried some 20DP gears with a hex bore on my Onxy One, and the teeth held up fine–while the hex bore rounded out pretty quickly. Tried it again with a metal hub and it worked surprisingly well. The teeth held up and transmitted torque just as you’d want them to–though I’ll have to test the heck out of it in the off-season before I try it under any critical load.

As to the OP, the Onyx One is more than acceptable for FRC purposes, IMO. We made various brackets and mounting hardware for our 2019 robot and they held up extremely well. I’m curious to see how those same parts last in a fall off-season, when the nylon has had plenty of time to absorb moisture from the air and become brittle.

We found on some pulleys we printed with a 3/8" hex bore for our cargo mech that the hex started to round out. We broached them out to 1/2" hex and put the 3/8" to 1/2" hex adapters that WCP sells (and made some of our own) and it seemed to solve the problem.

So I guess lesson learned is the face width on 3/8" hex bore isn’t quite big enough, but 1/2" hex seems to be. We will likely continue to print pulleys and use this practice again in the future (currently using it on our off-season swerve module).

1 Like

We rounded out a 1/2" hex, but had a lot of torque on it. A Versa Hub pattern distributed that load nicely, though, and it held up just fine for what little time we played with it.

This season we gained access to a Mark 2 through my work and we printed approximately 15-20 unique parts for our robot on it. All were printed without any reinforcement because, as others have stated above, it was not found to be necessary. I’ve included a picture below of the most critical/load bearing printed part that we had on our robot this year. It’s an elevator brake that functions by clamping the lift belts for the first stage of a cascading elevator into the fixed tooth profile and relying on the tooth shear strength of the belt to hold the elevator in position. This was used only during our climbing sequence where after deploying our suction pads and lifting the robot into the air, two of these assemblies clamped down on the two belts on either side of the elevator to hold the robot in the air even after power was cut. Each brake has a single “U” shaped printed part where one face has the inverse belt tooth profile, one face has the mounting pattern to fix the part to the frame of the robot using 3 #10-32 bolts, and the final face has the mounting pattern for the pneumatic cylinder. We were slightly concerned if this part would be durable enough to last but we used it through DCMP and CMP with no problems. For reference it was printed at 100% infill Onyx only. After our experience this season, I would recommend any team invest in one or more Onyx Ones rather than a Mark 2.

3 Likes

We have not rounded a 1/2in hex yet but we had a 3/8 skip and emploid the same solution you did. What material did you round? was it the Markforged Nylon? What is important with hex seems to be very tight. I.E. it becomes a press fit. And high load? That is relative we lifted 1/2 robot with one on a 1in diameter gear. (front or rear elevator)