[danmcgee]

I have been looking for a set of plamns to build a CNC Router table that I could use to cut thin aluminum on for some aircraft parts. I came accross this site by Tool Comp and they offer a set of plans and a really good build document and support for thier table. $100 here is the web site.

http://www.machinetoolcamp.com/DIY%20CNC%20Routers.htm

Before I pay for these plans is there any comments from the CNC community about weather I would be waisting my money or if these plans are good to build a solid table. Comments from someone that has built this table or one from the plans of any size would be welcome.

Thanks Dan

[jsheerin]

It looks reasonable. You could design the same machine by spending the time to do the research on this forum, so essentially what you're paying for is them taking the time to do that for you. That manual does look nice from their sample. I would change a few things on the frame design, but it's nothing that is really bad - I'm sure the machine would work fine as is. The only things that bother me are that I can't see what the drive system is - screws or rack and pinion? - and they don't give very complete specs, the biggest omissions being how fast it can rapid and cut.

[danmcgee]

I was looking at useing Roton high quality screws and getting my electronics from http://kelinginc.net/index.html I think it is a G540 system.

What would you change about the frame designe I am only buying the plans so I have a place to start. I do not have the time to do all the research here to build my own nor do I know enough about CNC to know what right would look like.

I am learning Solidworks wells and am sure I can run the CNC without problems but do not want to wasit time and money. I need a table that will have a cutting area of 4X8 and can cut .125 think aluminum and smaller. Would like to get as close to .001 persion with a tollerance of at least .005 repeatable.

Let me know what you think

Dan

[jsheerin]

Personally I would do dual drives on the X axis and support the bed at more locations than just the ends. It looks like they are possibly driving it in the middle and have the linear rails under the table. For the gantry, where they have a top and bottom rail, I would connect those together. This would give it much higher stiffness, but it might not work with how they have laid out their drive system.

[danmcgee]

I will support thwe table along it's entire length to make the table more sturdy. Some one else also told me to use duel screws for the X axis and also for the Y axis depending on length. I would want to move the drive system out to the sides to drive the table using the best stepper motors folks on here seguest and best screws. I only want to do this once.

If you have a great design then I am game.

Dan

[jsheerin]

I have an okay design. Pics here:
http://ldsg.snippets.org/HORNS/images/cnc/

I'm working on a new design that corrects the issues I've had with this one. However the biggest issue for me is speed - my current router won't go as fast as I want. That's why I say it's worrisome to me that they do not spec that out. Yes, you could change it, but I imagine they have it designed with certain parts and I would be interested in what that was if I was building that router. When you start changing things, the changes have a way of rippling through the rest of the design. For example, I am switching to servo motors instead of steppers. That requires new motor controllers. They require a different (larger) power supply. They also will require a different breakout board to interface with the computer, etc.

[danmcgee]

Well your design certianly cuts aluminum well. Your frame constrcution looks like tha same or like material the DIY one uses.

Would most likely never be cutting alum that think but cool if it could.

Dan

[jsheerin]

Yes, mine is 80/20, and I imagine theirs is too. I bought all mine on ebay surplus.

I just cut aluminum in very thin passes - usually around 0.020" per pass at around 20-40ipm.

[danmcgee]

Cool the skins of the aircraft are only .020 in thickness so you could cut it in one pass. Most of the airc raft is this size some is smaller.

So I am not palnning on cutting large sectuion of aluminum just some thin stuff size is the only issue or I would build a much smaller table.

Dan

[oeffner]

google Mechmate free plans, lots of support on their forum, well proven design

[danmcgee]

I have the MechMate plans but would like to stay away from the welded steel frame and the foot print of the machine is much larger. I haved also gotten some real negative feeback about excessive backlash in regards to the MechMate built per plans, however I may still decide to build that design depending on the information I get here.

Has anyone had any experiance with this DIY machine from Tool Comp. I do know they offer ready made comercial machine with a good record.

Dan

[Gerald_D]

Post deleted

[danmcgee]

What is there to explain Gerald? in my research for the right cnc to build I got several negative comments about the MechMate haveing excessive backlash. Design real massive. I have no desier to waist money so comments from the CNC community are taken as is. If you would like to give positive feedback inregards to the MechMate the design is not off the table.

Dan

[Gerald_D]

The only point where backlash has been mentioned in relation to MechMate is within the off-the-shelf geared motor from Oriental Motor. The use of this geared motor is not mandatory - other folk have used direct-drive motors or tooth-belt drives. I really do not know of any other area where MechMate builders/owners/users have expressed a concern about backlash.

And even then, in the lone case where one builder complained of excessive backlash inside his geared Oriental Motors, it would appear that he simply had loose set screws on his drive pinions . . . . . but he doggedly insisted that the backlash inside his choice of drive motors gave him huge accumulating errors. Many others use those geared motors without any complaints.

[danmcgee]

GD, thank you for your reply on the MechMate, I have gotten that same response from other MechMate builders on the MechMate forum, and does seem to be related to the type and often just the particular manufacture of the hardware being used by the builder in result of poor performance.

My deciding factor now is just plain from a convenience point the design I have chosen requires no welding, provides the same cut area with a smaller footprint and that was the most deciding factor. In having said that I still have to sell my house and get another one here where my job moved to and the footprint size may end up not even being a factor at all.

I would like to point out that I really appreciate all the responses and information I have gotten and learned without anyone getting in a pissy mood with me over what is obviously my lack of knowledge and understanding of CNC operation and construction, I have learned allot and truly believe I will build a good CNC table to accomplish what I have set out to do.

Thank you all very much.

Dan

[DIYaholic]

danmcgee,
Once you get "settled in", in your new place, remember to start a build log! Everyone loves pic's & video.

BTW: Good luck in your new surroundings!

HINT: Buy a place with a HUGE basement/garage/barn. Or,you could just build/put the machine in the livingroom (who really needs a livingroom, everyone hangs out in the kitchen anyway).

Randy,

[danmcgee]

Randy that made my day, just the right kind of funny to start out with. I will bee looking for a place that has a large garage hoping for at leasty a three bay or 4. If not I will build one to suit me needs.

I will want to close one bay off just for the CNC and the other 2 for building aircraft or working on one of the cars, or build so I could do the same. Not to leave out thwe fact there must be enough land to put a 1500 ft flight line on as well.

Dan