lol no. And Jackie doesn’t work for us anymore. She was pissed off that we never got our kits we ordered on Kickstarter (and we still did not get all of them).
Excellent!
Thank you.
And I am thinking that while the M4 seems very well thought out, I am not very knowledgeable about 3D printers and CNC machines, yet I still have some concerns regarding durability and precision.
One concern is that vibrations and other environmental factors may impact the life expectancy of components (like you had to replace the boards using the rj45 connectors already which might not have been a necessity if they had a different location), and placing the drums with the belts on the sled might have caused some other compromises to make everything fit.
Having slightly longer cables and placing the components in fixed, less vulnerable locations seems like a good tradeoff to me.
So if there is a way to move the belt drums away I would be interested in trying that.
David Lang wrote:
not saying your approach can’t work, but explaining why the maslow 4 was
designed the way it is.
oh yes, one more complication, the effective length of the belt and the anchor
location change depending on the angle of the belt (how far the belt is wrapped
around the sprocket at the corner).
the math gets really ugly, and that complexity is why we had so much grief with
the roiginal maslow.
keeping the belt directly in line with the center of the anchor and center of
the pit is a DRASTIC simplification, and it’s what lets the system do the
calibration to figure out where the anchors actually are (measuring the anchor
locations was also a problem for the original maslow)
I’m less worried about the electronics being vibrated than you are. When there
aren’t sockets, solid state electronics are really good at dealing with
vibration.
but I’m not an expert in the field, just an interesting hobbiest
and they person saying something can’t be done should never interrupt the person
actually doing it.
So I’ll continue to pass along info as I think about ot of the problems I expect
you to have, but look forward to you showing me what I missed that makes it work
David Lang
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I understand that a lot of work has gone into this, and I am very thankful for the effort.
But I am still left wondering why is it not possible to take the belt drum assemblies and place them on the corners of the frame.
Simply switching places, I will trust your statement about the math involved, but if there is a way to simply switch places between the end pins and the belt drums, is there really any difference in the math?
The only difference I see is potential for reducing slack and the option to make the assembly surrounding the router from something like rolled steel which will have drastically more wear tolerance.
The assembly around the router would probably benefit significantly if it was made from steel, small specks of dust in between the mechanism will likely cause the plastic to weaken over time from the friction.
Like you say, not concerned about the electronics, but I am concerned about the connectors and some of the solder joints.
I apologize for barging in here and making noise, not my intention. Looking for something that is durable and precise, and I am attracted to alternative solutions. Seeing an opportunity to increase durability with little extra cost, and more durable components usually bring a better long term stability that might help increase precision in a small way.
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KaffiMann wrote:
But I am still left wondering why is it not possible to take the belt drum assemblies and place them on the corners of the frame.
Simply switching places, I will trust your statement about the math involved, but if there is a way to simply switch places between the end pins and the belt drums, is there really any difference in the math?
If you just switch places, it will work. you would have something like the arms
on the sled, just without motors/spools in them so that the anchor on the sled
has the belt pointing directly at the bit (or it could be a ring with sliding
anchors like the original maslow)
and the motors/spools would go on pivot points at the corners of the anchors,
not offset from that with the belt going around a pulley at the corners.
that would work. It would not change the math (other than some trivial
constants)
The only difference I see is potential for reducing slack and the option to make the assembly surrounding the router from something like rolled steel which will have drastically more wear tolerance.
The assembly around the router would probably benefit significantly if it was made from steel, small specks of dust in between the mechanism will likely cause the plastic to weaken over time from the friction.
on the other hand, steel rusts, if you are looking for long term durability,
bearings are needed instead of just sliding joints.
I don’t know how many hours of cutting Bar has on the machine they use.
Like you say, not concerned about the electronics, but I am concerned about the connectors and some of the solder joints.
I apologize for barging in here and making noise, not my intention. Looking
for something that is durable and precise, and I am attracted to alternative
solutions. Seeing an opportunity to increase durability with little extra
cost, and more durable components usually bring a better long term stability
that might help increase precision in a small way.
it’s sowth talking about.
David Lang
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Hmmmm. Is there a way to program an hour meter…like a cars odometer but for hours (like farm equipment). Could it be viewed/supported in the software?
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How about distance also.
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Could we reduce from 4 belts to 3 in a triangle pattern. It seems like it would reduce the arm angle limitations and give better access in the white and red zones.
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I think the forces caused by the geometry of the belt angles would get worse as you get further from center and would cause the same inaccuracies that where the problem with the original maslow on the sides and corners
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Dano wrote:
Could we reduce from 4 belts to 3 in a triangle pattern. It seems like it would reduce the arm angle limitations and give better access in the white and red zones.
for a machine that uses anchors in the ground yes, but it would not be practial
for a vertical machine.
Also, the pattern would be very different, triangular, and not a good match for
the pieces of wood that are available to buy, so the result would be so much
larger that you probably lose some accurace from it.
David Lang
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Found some suitable V groove rollers here:
And something like this welded mooring ring should work?
Will keep looking.
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KaffiMann wrote:
Found some suitable V groove rollers here:
And something like this welded mooring ring should work?
sorry, I’ve ;pst tracl pf tje cpmversatopm. os tjos fpr a ring on the sled and
bearings riding on it instead of the spool on the sled?
you need a larger ring, but it can be cut from sheet metal, look at the original
maslow for an example of how it can be done.
I can’t tell the cost of the bearings you are pointing at, but here’s a cheap
option.
Also, the small wheels that 3d printers use also come in a version that has a
v-grouve tire on it (don’t know if they would be strong enough, but metal ones
like I show above clearly are)
David Lang
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Make the machine more rigid
Over the past month I have been unable to use the machine due to a z axis motor stall problem. A big contributor is the machine is not dynamically rigid in the y axis (see my post).
The fix would be to extend the lead screws to the same length as the linear bearing rails, add a ring bearing to the top, and put plastic vertical buttress supports that house the ring bearings (basically duplicate the plastic buttress support of the linear rail on the sled’s y orientation.
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I made a point out of choosing Nylon because it is often more durable than steel in certain applications.
Thank you for the alternative, am looking at options for rings, like you said I am thinking about a 300mm diameter ring made from two halves aligned with brackets and mounted with standoffs.
KaffiMann wrote:
I made a point out of choosing Nylon because it is often more durable than steel in certain applications.
I’m just nervous about the concentrated force. but if you want that, look at
these
Thank you for the alternative, am looking at options for rings, like you said I am thinking about a 300mm diameter ring made from two halves aligned with brackets and mounted with standoffs.
make them bolt to the towers, eliminate standoffs if possible (just one thing to
get in the way of belts/hoses/wires)
David Lang
2 Likes
I hear you, but I think 4 standoffs would be good for extra rigidity, will most likely have more room for movement than the way it is now.
Steel rollers often crack much faster than nylon ones wear.
Thank you for the link.
Added to this suggestion of preassembled parts. If they are done in a low cost country with low import charges to Europe then we could get replacement parts without facing $70 delivery and import duties costs.
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How is China for you?
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China is good. Lots of items from there seem to come to the EU without much duty and only sales tax (vat). I think it depends on whether it’s classified as electronics or not.
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I shared a solver function that would do the math in the order needed for calibration in another thread talking about this awhile back when dlang raised the same concern. I’m not 100% sure if a similar function can be written in the language you’re using for calibration, but I would assume it’s highly likely. The modifications this would need, beyond being written in the appropriate language, should just be minor geometry changes (like the recent accommodation for the belts not actually traveling in a straight line to the anchor points).
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