I’ve elected to not put this in my build log, as it is a question about hardware development, and I’m asking for help, not “building” my build.
I bought two different brands of 2.5" flex hose. One was thicker, harder, less flexible, but it was a short length, not long enough. It was more expensive. Another was softer, more flexible, and it was long in length. It was more affordable. I used it because it could do the full run for Y axis and X axis, with plenty to spare. But it’s too floppy. On the X axis (gantry) which is the shorter of the two, it’s fine. But only the Y axis (long run) it needs support. Two problems are happening. 1. During motion in Y axis, the machine does a hard stop with an error thrown. I got the sense that the hose had gotten against the limit switch. (Can that cause a stop even when not homing? — EDIT: yes, at least in my config setup). 2. Even if I used a printed extension to keep the hose away from the limit switch, the lack of constraint means if I get very far along in the Y axis direction, the hose sags down onto itself and gets tangled up.
Anyone have ideas on best way to constrain the 2.5" flex hose? Like a drag chain but bigger?
Your limit switch is triggering during any Y motion or during homing? If during any Y motion then you have changed that in the config and your problem is the exact reason Ryan does not turn that on.
As far as it being floppy down Y I don’t have a good answer for you other than add more support. This is one of the main reasons I bring my dust collection drop down at the middle of the table in Y. I can keep my hose shorter and it can hang beside the table and run back and forth with the LR4
Your nudge made me realize I had made an assumption, which may not be correct.
Twice during regular jogging motion, not during homing, the machine halted suddenly with an error thrown, and when I looked the second time, the hose was against the limit switch. I will investigate further on this. In the meantime, I edited the OP to soften my assumption into a question.
OK, so my assumption was correct, at least in my current configuration.
I just did a test. It may be because I have limits enabled (soft and hard) in my config, but when I am in regular jogging motion, if I press the limit switch in on one of my side assemblies, the machine halts instantly and throws an error.
I am dropping mine down in the middle of my table, but I may not be doing mine like yours. Would you mind to post a photo of yours at both extremes, or a video of yours doing full range of Y axis motion?
In general, both soft limits and hard limits are an unnecessary complication on these machines.
If you travel too far, your motors will skip, and it’s the same effect of a messed up job that soft limits will have when it stops motion in the middle of a job, or hard limits for that matter. All of them result in a likely messed up workpiece.
However, no limits enabled means the fault can’t be accidentally triggered.
It should be pretty easy to not run a job that travels outside of your machine limits, though.
I gather that with only soft limits, if there are skipped steps, the machine is now not where it thinks it is, and it could do a crash, despite the soft limit. With a hard limit, there’s an added layer of protection, but only on an end where a limit switch can meet an end stop and trigger. Since I don’t have both the Y limit switch sockets populated on each side assembly, I am only getting the added protection on the Y min end of the table. I might just turn off the hard limits.
I guess I’m confused why you need the added protection of either soft or hard limits??
When you set up a job, to make sure you don’t ruin a workpiece, one of your first steps should really be a “framing” of the job like you would do with a laser etc, to make sure it fits where you have it laid out.
Any travel limit violations should be found ahead of time.
Finding them out, in any of the 3 forms, in the middle of a job, is asking for more trouble and cost than it’s worth
The problem with using limits is exactly what you are seeing now. If you are in the middle of a full sheet MDF cut for your products and anything touches that limit switch it’s halting. What will that do to your product when it happens?? I don’t know because I don’t use them. So I can’t say for sure. But I would think you could possibly end up with a blemish that scraps the part
Now on the flip side. I have accidentally ran my LR to the Y max and it hit the belt holders and skipped steps. So what. All I have to do is re home and I’m golden. There should never be a time that I hit the belt holders during a job. If your table is THAT tight then you might think about adding a little length somehow to move your belt holders away from the job by a few inches
Re. the limits, I aim to disable the hard limits. I think that will get me away from this issue.
Re. the saggy tangled hose, for a bit of context, this is my first time trying to set up flex hose like the docs suggest. On my LR2 and LR3, I did not do flex hose like that. So it’s all new to me. Still trying to get it right. I have the X movement working. Trying to get the Y.
OK, so I disabled hard limits, and then re-ran the test. Indeed, now the limit switches are only effective during homing. With soft limits still enabled, triggering a limit switch during regular motion does not cause a hard stop like when hard limits were enabled.
Also, @Jonathjon thanks for being willing to post pics, but I just did a quick test with shorter hose, and no tray, and the hose looks like it will be OK without the tray. I was probably just over thinking it and over complicating it. I’m cutting my hose shorter, and will give this a try.
I’m having trouble imagining why it’s tangling. If you make the tray a little deeper it will constrain the hose - sorry about the odd angles - just trying to photograph it so it makes sense.
Note this is my 2" hose not your 21/2" - a slight roundover at the top of the tray will also help.
My hose “drop” was close to the middle, and my tray was from the middle to the Y-min side. When the gantry would move to the far end, past the the tray, the hose there was dangled over nothing, would sag down, and then catch on itself while trying to return. I can see how a full length tray and longer hose could work. In my new setup / attempt now, I’ve gone the other way: shorter hose, no tray at all, and will report back.
EDIT: more context: the hose I had in hand when I planned my tray, was pretty stiff. But it turned out to be not long enough. I then switched to another hose that was longer, but more floppy.
