MechMate "Style" CNC builders

[Axel1966]

Hi all,

I read a lot of treads about "MechMate style" CNCs, especialy from guys who's realy afraid about an "english spoken" technical website.
So they're trying hard to find good building solutions, conducted by their own faiths, or with the hazardous goal to save time and/or money.
I appreciate I did the same mistakes at the start.

I thought it could be useful to list worst trys to prevent new coming builders to walk those ways...

Here's some views of an engineering from a general CNC website.
I do my best to warn the builder about problems to come :
Pics below
Note the V-rail replacement is from an aluminium corner...
Pics below
Note the gantry will be up to 2500mm width.
Pics below
You'll see by yourself what is worrisome :
- Table stiffness, guidage of X and Y.
- Structure of the gantry cross bearers.
- ...

Well, at this point, the builder wants to proove me his solutions are relevant.
I am afraid of not being convincing enough... :(

[danilom]

Just have to congratulate the author on the most complicated upgrade ever seen :)
if this is going to save money time or anything else it would be a miracle.

I like innovation so I registered to view the pics, and here they are for others to see.

http://cnc.rs/mechmate/ludi_mechmate/vue1.JPG
http://cnc.rs/mechmate/ludi_mechmate/vue2.JPG
http://cnc.rs/mechmate/ludi_mechmate/vue3.JPG
http://cnc.rs/mechmate/ludi_mechmate/vue4.jpg

[smreish]

...how to do you square the gantry post fabrication?
Looks like a lot of work to do the same thing the MM does normally. Is there a reason why you have to depart from the design so drastically?

[KenC]

impressive simulation.
How about painting the machine any color other than white. will have a much better visual impact when hanging the poster on the wall.

[Axel1966]

...how to do you square the gantry post fabrication ?
IMO, there's no triangulation on his gantry, so first, it cannot stay in any shape, squared or not. The worst of all is the two c-profiles sticked together with PMMA glue as cross bearer...

[normand blais]

fail



you guy can laugh ,all french mm are not build the same

here is the link I could not put just the pic
http://www.usinages.com/projets-fraiseuse-portique-usinage-cnc-f43/mechmate-derniers-details-premieres-realisations-t24979-480.html

[smreish]

Normand,
No laughs on my part - I was just trying to determine how you would get the rollers, that are set at 90 degrees to a 90 degree shape would allow for the gantry to be squared. A lot of DIY CNC machines use the roller on the shape - nesting to a shape for a linear rail system.

Even with eccentrics on the bearings, I don't think you would have enough travel to square the unit quickly and reliably.

Good luck with your choices.

Sean

[normand blais]

Hi Sean I dont think I would post it here if it was mine ,still have a little pride :)

It is not nice to make fun of people... but I cant stop laughing.sorry

I went to that site that Axel mention is trying to help a builder .

It is sad to see all the waisted time and stuff to end up with this socall Mechmate

The worst I think the bad image it give of mechmate

[Axel1966]

I agree with Normand about that bad image.
I did not made this topic to laugh on anyone. There's no glory to do this.
I made this topic to group all the worst "good ideas" around the mechmate
and the explaination of why this should not be done.

The main argument here is "follow the plans or go to CNC zone".
This is short, and does not explain a lot.
There's a lot of topics explaining what should be done.
But no topic explaining what should not be done and why.
IMO, it's a big lack in the temple of regular MechMates.

Furthermore, it will prevent several endless questions and comments about MechMate "improvements", that upset most of the early MechMate builders.

[normand blais]

I think this is all you need of bad idée to figure that it is best to stick to the plan .
And if they want to experiment they should not call it mechmate or come arguing here .

:rolleyes:

[Axel1966]

Well it's a respectable point of view.

There's a myth aroud the MechMate.
A lot of people says the MechMate :
- is not accurate
- have guides not straight
- have a dangerous flying gantry
- must be slow
- and so on...
All a mythology around the MechMate,
based on feelings or chat between unwise people.

The truth is the MechMate is a good polyvalent machine, great value for money.
Fast and easy to build, and the MechMate do not need any major improvement to work perfectly.
Most of them would build a regular MechMate, if they new that.
I thought it could be more explicit in the MechMate forum.

Instead of kicking'em out and let them build FreaksMates,
there should be a way to federate them and provide help
to build more nice looking/working regular MechMates.

[bolingerbe]

After looking at the site Normand posted I am at a lost for words. :rolleyes:

[KenC]

Me speechless too...

[MetalHead]

In my view folks that think they can innovate will bring ideas to the group and talk about those innovations. Then things like Belt Drives, Single Piece Stop Blocks, Motor Plates, Cable arms and rack will come out of those threads.

Those that only want to create, fail, create, fail or create again and again will go off the tracks when building a CNC machine. This forum is not the place for those folks and why so many people struggle over on the zone to ever really finish a build.

Our machine works and when we see a possible improvement (Like 5th axis plasma capabilities- way cool by the way !!!) those are reviewed by everyone and while maybe not in the official plans, you learn through your research of this site what all the MechMate can do.

So everyone that builds "off plan" machines may have found (especially a first timer) that sticking to the plans is the fastest way to a true business class machine that can deliver results.