Can we switch to a linkage arrangement with the next shipment of maslows?

[MeticulousMaynard]

@bar

Not to muddy the waters further by throwing a third option into the fray but the goal is to ship the next batch with the ring as the attachment system.

Holy damn that’s awesome! I hope that in my previous post it did not sound like I was ruling out the ring approach. It has some possibilities to actually outdo the linkages as far as accuracy. I know that the early versions it skipped as it moved and Logan had mentioned in the triangular kinematics development thread that the linkages work better with the forces available. However, it doesn’t have the same opportunities for compounding errors that the linkages have if there is any play in their connections. I know that is an issue for the top mount, not sure about the 45 degree version.

Which brings me to:

@dlang

What do we need to do to make this happen? can we do it fast enough to not force the next batch of users to have to buy something extra or suffer with the stock kinematics?

While what we have right now for linkages might actually be perfectly fine, I err on the side of caution. We really need to do more tests and trials to see how well each system works and where they are going to encounter issues. What if we sent out one of the linkage systems with the stock machines and they have a critical flaw with compounding errors or wear? Even if an issue doesn’t come up during regular use, every machine is going to be pushed to the extreme at some point, and that could trigger a bigger problem. I deal with these kind of issues on the shop floor every week when we make a system change and it has unintended consequences. Are we expecting that all these new Maslow operators are now going to have to deal with these problems?

That being said, in erring in favor of caution, this does slow down the development process. The last thing we need is to become a bureaucratic mess and get in our own way. So maybe the correct way to move forward is to ship the ring as is Bar’s goal, AND send out the original brackets so that the operators have the option to to back to quadrilateral if issues do come up. I know you say that using the original kinematics is “suffering”, but I ran my machine for a few months using that setup and it really is good enough to get acceptable results.

@dlang

This is one place where I think the 45 kit is behind, it requires more mounts in precise locations. It’s hard to be precise before you have an accurate machine to work with (although as I noted earlier, you can drill the holes based on the linkages)

the top mount kit requires only two holes in the riser, vertically in line with the bit, so it’s easier to mount

the ring kit can be centered with a printed circle jig (as long as that jig is not distorted too much when it’s printed)

I think there is a bit of misconception with the stock kinematics being “inaccurate”. Yes, quadrilateral will begin to distort at the left, right, and top dead center of the machine. But the stock sled is only 18" in diameter. I was able to cut out a sled for the top mount linkages WITH the mounting holes using a stock sled, and the hole placement is exactly where it needed to be. When I checked the hole placement with the linkage arms, in the same manner that you had suggested to locate the holes on an existing sled, it was dead nuts. I think that any operator going through the build process should be able to get the same results.

In my previous post, I had said that the temporary sled could be used to cut the linkage sled. I misspoke there. I do not like the temporary sled. In the brief amount of time I used it, it was unstable, unpredictable, and a pain to use. I would agree with you there in saying that using the temporary sled for any length of time is suffering. I would like to correct my previous statement and instead recommend that the 18" round sled with the stock mounting solution could be used to cut that SVG file. I would edit my previous post, but I think that anyone reading through this thread might loose a bit of context in our discussion.

@dlang

so if the top kit had one more pre-made piece that the links connected to at the center, and attached to a metal bracket, that would satisfy you? It would be pretty easy to add one more piece that also had a couple holes in it to attach to brackets like the Z axis uses. I didn’t bother to do that because a 2x4 on edge seemed ‘good enough’ and saved a few bucks. but it could be done pretty easily if needed.

This would certainly bring it more to the same level of “completion” that Bar’s ring solution has. I still think that an SVG file would be the best way to move forward, but giving the user the ability to easily modify an existing sled. As @Blurfl said, then it becomes more assembly and less construction.

@dlang

I would LOVE to see direct comparisons between the different options.

Me too! It’s on my to-do list, along with feedrate tests, a proper z-axis, implementing M codes, and far too many other items. And this is exactly your argument. We are relying on a group of people to do these developments at a hobby level, which means that work, family, health, etc are always going to get in the way and slow the process. Any chance @bar will hire us to do these developments as our 9-5?

Ultimately, however, I do agree with you David. The linkages/ring should be the stock option for the machine. The issue that I, and I believe @blurfl are arguing is how do we go about effectively implementing it in a way that doesn’t negatively affect people coming into this?