New Boy introduction

[Crunch]

Hi
My name is Paul,
I am right at the start of a cnc router build, I have been reading on here for some time now gathering as much info as possible,
This is all new to me so please be patient with me,I have a massive task ahead of me as I have no back ground in cnc at all, I've always been interested in engineering and fascinated with cnc. I spend most of my time tinkering with motor bikes , model helicopters, or anything mechanical.
I have a small lathe, which i have learnt loads from and quickly realised it is not as easy as the pro's make it look.
I'm learning fusion 360 cad and cam and watching as many videos as possible,
My build
Cnc moving gantry router all steel construction, it is based on image attached, but want to use 200mm x 100mm box steel for gantry ,fit ball screw inside and cut letter box for ball screw, ( I have a choice of 4.5mm or 8mm thick ), with the cut out in the front don't know which to use for strength purposes, also weight.
It's made from 70 x 70 X 5 box steel for the router frames,
It's 1200mm wide x axis and 1000mm deep y axis
20mm square linear rail X Y Z
1 x 2010 ball screws on x axis ( only because of what I've read, don't know if 16 will do ?)
2 x 2010 ball screws on y axis ( again what I've read to stop whip )
1 x 1605 ball screw on z axis
All with pulleys and belts, need help with ratios, nearer the time.
When I started to think about this build I was set on using nema 34 8nm closed loop stepper motors, as bigger was better, I soon learned that was not the case, and holding power number is not the one to look at.
The stepper motors is where I am really struggling as my machine will be heavy as I want to cut aluminium. But all this reading has been worth it as the one thing you tell new comers is not to buy any electrics which I haven't,
Sorry for the long post, I have so many questions but will ask as I need to.

Great forum, so much info.
Thank you Paul

[driftspin]

Hi
My name is Paul,
I am right at the start of a cnc router build, I have been reading on here for some time now gathering as much info as possible,
This is all new to me so please be patient with me,I have a massive task ahead of me as I have no back ground in cnc at all, I've always been interested in engineering and fascinated with cnc. I spend most of my time tinkering with motor bikes , model helicopters, or anything mechanical.
I have a small lathe, which i have learnt loads from and quickly realised it is not as easy as the pro's make it look.
I'm learning fusion 360 cad and cam and watching as many videos as possible,
My build
Cnc moving gantry router all steel construction, it is based on image attached, but want to use 200mm x 100mm box steel for gantry ,fit ball screw inside and cut letter box for ball screw, ( I have a choice of 4.5mm or 8mm thick ), with the cut out in the front don't know which to use for strength purposes, also weight.
It's made from 70 x 70 X 5 box steel for the router frames,
It's 1200mm wide x axis and 1000mm deep y axis
20mm square linear rail X Y Z
1 x 2010 ball screws on x axis ( only because of what I've read, don't know if 16 will do ?)
2 x 2010 ball screws on y axis ( again what I've read to stop whip )
1 x 1605 ball screw on z axis
All with pulleys and belts, need help with ratios, nearer the time.
When I started to think about this build I was set on using nema 34 8nm closed loop stepper motors, as bigger was better, I soon learned that was not the case, and holding power number is not the one to look at.
The stepper motors is where I am really struggling as my machine will be heavy as I want to cut aluminium. But all this reading has been worth it as the one thing you tell new comers is not to buy any electrics which I haven't,
Sorry for the long post, I have so many questions but will ask as I need to.

Great forum, so much info.
Thank you PaulHi Paul,

You have come to the right place.
It is good to see you have made work of designing the machine.

Hope you will find the information you are looking for on here like i did.

Grtz Bert.



Verstuurd vanaf mijn SM-A320FL met Tapatalk

[mekanik]

Hi Crunch
Welcome to the forum,Theres loads of information available if you can wade through the build logs, regarding Gantry construction i would like to point you @ Neals log.
http://www.mycncuk.com/threads/11617-AVOR-%C2%96-a-steel-framed-medium-size-router/page3?highlight=AVOR
I like this a lot.
Regards
Mike

[Crunch]

Thank you for your replies.
I have made a start based on image I attached.https://uploads.tapatalk-cdn.com/20190430/5901f925de15acbce84949b7c4e2e194.jpghttps://uploads.tapatalk-cdn.com/20190430/0964397a4258d31cdc25dedfa044e155.jpghttps://uploads.tapatalk-cdn.com/20190430/94729e833eaeb1013ea8a3676b6f8a85.jpghttps://uploads.tapatalk-cdn.com/20190430/1f0a0499205e05b4573879b257e0a530.jpghttps://uploads.tapatalk-cdn.com/20190430/f86f768ba8fbe2f78a339814a8dfd836.jpghttps://uploads.tapatalk-cdn.com/20190430/b24629148676a08d1275b09e582544c0.jpg

Sent from my SM-G900F using Tapatalk

[Crunch]

I plan to put sheet material around the 2 sides and the back to help contain the mess and set up a vac for doing mdf.

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[mekanik]

Frame looks solid, don't like the large box section you are intending for the gantry, better to have two square sections welded together, did you look at AVOR.
Regards
Mike

[Crunch]

Frame looks solid, don't like the large box section you are intending for the gantry, better to have two square sections welded together, did you look at AVOR.
Regards
Mike

Hi Mike
I had planned the side braces very similar to avor's design , don't you like the box section for looks or strength.
I based my idea around the attached image, but to sit the gantry on a plate then on the cars as avor's design with end braces like avor.

Thanks Paul

[mekanik]

Hi Paul
Nothing to do with cosmetics, two square sections welded together will be far more rigid than a similar size one piece component.so you can have it looking as per the shop sabre but it will be more rigid, just pointed you to AVOR as others have commented on the gantry design and though you might find it appealing.
Regards
Mike

[Crunch]

Hi Paul
Nothing to do with cosmetics, two square sections welded together will be far more rigid than a similar size one piece component.so you can have it looking as per the shop sabre but it will be more rigid, just pointed you to AVOR as others have commented on the gantry design and though you might find it appealing.
Regards
Mike

Hi Mike
Thank you for your time , I read the Avor build which was very detailed, Any help or advice is greatly appreciated. This is all new to me and I'm happy to be advised, shown different methods etc,
I spent a lot of time looking and reading to choose a design that will fit my needs and fit the garage space. This is why I joined this forum for advice from the people who have been there and done it.
I would like to use the box steel if possible just because I've paid for it, even if I had to weld some braces inside to strengthen it. I would be willing to change it if it was needed.

Regards Paul

[Crunch]

I have a few questions, if this is not the right place to ask please advise where to post.

What is an acceptable weight of a gantry with every thing on it including spindle, it terms of performance, I understand the heavier it gets the more effort it takes to start and stop it when moving due to the mass. Do you just deal with the extra weight with gearing or bigger steppers? Or is there a sweet spot in weight ?

I'm not 100% sure on how the axis are, as some machine I've seen shows front to back as x axis and others machines x axis is left to right.

Also which ball screws would be best to use,
2 x 900mm 1605 or 1610 with pulleys y axis. ( front to back ) or
2 x 900mm 2005 or 2010 with pulleys y axis. ( front to back ) would you get whip on this length and would these be better with a heavier gantry?
1 x 1200mm 2005 or 2010 with pulleys on x axis ( left to right ) again for whip due to length .
I've based axis direction on most machine I've seen are this way, but there are many that show they are the other way.
Which is correct ?
Do you know why different machines show different ways ?

Regards Paul

[Crunch]

.

[mekanik]

Hi Paul
Others (who have actually built a machine) would be better to give advice regarding gantry weight ect, but as you say you want it as rigid as possible and also not too heavy.As a general rule the axis are usually X longest Y gantry and Z for the virtical. our cousins from across the pond sometimes do it differently, it,s a pitty you didn't open a discusion before you started your build as if you are strugling with floor space you had the option of making a semi vertical layout.
Good luck on whatever you decide, under no circumstances purchase any of your electrical gear before you have your design set, the weight of the gantry is an important factor regarding motor choice, and it would be better for you offer your design up for critique, the lads will put you right regarding motor selection.
As you want to use the box section you have already purchased for the gantry i would do as you said and put a length of flat bar inside across the narrow section, drill a series of holes in the box section and stitch it to the flatbar so get the same effact as two square sections, won't be as rigid as the latter but should be better than the box section as it is now.
Regards
Mike

[Crunch]

Thanks Mike

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[pippin88]

The convention for axis labelling is:

Standing how you will use the machine:
X is left and right
Y is towards and away from you
Z is up and down

It is this way because that is how you design things in CAD etc. It probably originates with labelling of graph axes.

[pippin88]

You want diagonal bracing in the tube, not a horizontal plate. This can be done by stitch welding vertical plates within the tube at a few places and welding on end plates.

The gantry is subject to torsion. Diagonal bracing is much more effective.