Monster Maslow Possible?

No Judgement
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HI guys i have been following the maslow for a while i think its such an inovative way to do cnc - I havent build one yet because i havent had the need but now i run a caravan manufacturing business … I would like to make one of these but way way bigger … im thinking a cut bed 10m long and 3m high … ill be cutting foamcore caravan walls with this monster machine , the actual cut part would be 8m by 2.4 and weigh 130kg and would be lifted by overhead hoist, since the material is a thin layer of fiberglass and then foam the cnc will easily cut the material

i have the space in my factory for an upright monster cnc but not a flat bed one

is this a pipe dream? my basic undertanding of this system is that the further away the motors are the more acurate the cuts … soo monster maslow could be awesome … right?!

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it’s not as simple as ‘further away is more accurate’ there are trade-offs

the further the motors are apart, the closer to horizontal the chains get along
the top, which requires more force (more powerful motors)

the longer the chain when fully extended, the more sag there will be, which we
don’t fully correct for yet.

However, where the maslow is not accurate everywhere, it is very precise
everywhere (aka, it’s very repeatable, even if it’s not where the tape measure
says it should be)

So if you tweak your design to correct any inaccuracies you run into, the
approach should work well.

you probably want to go with much more powerful motors than the stock maslow,
which means a bigger power supply and a modified motor controller. If you are
serious about this, I think the odds are good that you could pay someone here to
design you such a controller, but it will be substantially more expensive than
the low power ones (I’m thinking probably > $100 but I would guess < $300). but
find motors first.

also play around with the spreadsheet to find dimensions that work well and
don’t cause your tension across the top to skyrocket.

David Lang

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HI david thankyou so much for your input … i suppose in my case milimeter acuracy is not needed but repeatability is … generally the cut edges will always be covered by trim or doors or windows … so the smoothness of the cut isnt actually critical … and thats a good point about adjusting the linework to compenate for inacuracy at the extremeties …

with regard to the motors being closer to horizontal … im not sure i follow … i imagine that the height that the motors are mounted would go up as the width is increased so that the chains generally start perpendicular to each other … i imagine that the best way to find the motor mounting locations would be to find the center of the bed and then draw a line diagonally right and left perpendicualr to each other … right … doesnt his mean the resulting angles would be identical to the smaller machine at every single point over the bed?

also i like your idea about getting somone to design the controller im not the best person to do that by a long shot :slight_smile:

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HI david thankyou so much for your input … i suppose in my case milimeter
acuracy is not needed but repeatability is … generally the cut edges will
always be covered by trim or doors or windows … so the smoothness of the cut
isnt actually critical … and thats a good point about adjusting the linework
to compenate for inacuracy at the extremeties …

what I’m saying is that repeated cuts will be accurate to the sub-mm, but the
cut compared to the drawing may be off by several mm. It’s not just accuracy at
the extemeties, depending on how accurate your calibration measurements are, you
may get what are drawn as horizontal lines bowing up or down (with different
degree and direction of bow depending where you are on the work area). Overall,
we are working on finding ways to minimize these errors with improved
calibration, but if you are willing to tweak your design cut lines to correct
the errors, you can get a good, repeatable cut.

with regard to the motors being closer to horizontal

the chains getting closer to horizontal

… im not sure i follow
… i imagine that the height that the motors are mounted would go up as the
width is increased so that the chains generally start perpendicular to each
other … i imagine that the best way to find the motor mounting locations
would be to find the center of the bed and then draw a line diagonally right
and left perpendicualr to each other … right … doesnt his mean the resulting
angles would be identical to the smaller machine at every single point over
the bed?

if you move the motors further apart and keep them at the same height, it
improves the angle at the bottom corners, but hurts the angles to the top center

if you move the motors higher and keep them the same distance apart, it improves
the angle at the top center, but hurts the angle to the bottom corners.

play around with the spreadsheet and you can see what I mean

also i like your idea about getting somone to design the controller im not the

We’ve had a few people design controllers now, and I think it would be really
good to get a design that can handle much higher powered motors, but that will
require buying more expensive components and most people won’t need anything
that powerful. You will probably end up paying for components for multiple
boards to get someone to design and build one for you, but I think it will be
worth it for the community and it sounds like this will be very useful for you.

keep in mind that it’s relativly slow, but if you can have it cutting the large
parts while people are working on other things (and there is so much to be done
in the assembly that I expect that you can), then it will hopefully not be the
pacing factor.

David Lang

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I think if you ‘scale-up’ the design, you won’t run into problems with angles that @dlang alluded to. So if you want to cut something 5 times wider than standard sheet, then multiple the distance between the two motors by 5 and increase the height the motors above the work area by 5. So 10m board would require, roughly, a 18m motor spacing and 3m height above the board… If I did my unit conversion correctly. But that’s a lot of chain so bigger motors might be necessary.

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