Build Thread- CNC router for University College

[mcentric]

A year and a half ago I built this router. This was something I, by chance, put on my CV when applying for a workshop technician/advisor position at a University College, Department for Product Design. By strange coincidence this was exactly the kind of person they were looking for as they had, for some time, wanted to expand their workshop capabilities with automation/CNC. In other words, I got the job

As this is a fairly small department, we did not want to go overboard with the machines we purchase/build in this first stage. So this is what I have done so far:

I have just ordered a Sieg KX3S cnc mill for our metal workshop.

My challenge here was that the only machine the Norwegian distributor had in stock was the one prepared for Sieg’s proprietary control software, and thusly has a network port connector. I want to run MACH3 as this is what I use at home and what I intend to use on the router I am about to build.
I am fairly certain that the Sieg prepared machine and the MACH3 prepared machine both utilize the same breakout board internally and that it will be a fairly simple re-wiring job. I have emailed Sieg directly and hopefully they’ll be able to advise me

Now on to the main reason for this thread: The router build

My design is probably 75% done. I will document my design and my choice of hardware in the following posts.

My previous build was fairly lo-tech so I would immensely appreciate any and all feedback and opinions from you guys, so I can end up with an efficient and sturdy router for my students.

Mikael

[mcentric]

The main building material will be aluminum t-slot profiles from Rollco.

As they currently don’t have CAD files for their profiles I’m just using generic boxes with the correct dimensions in my design. I have color-coded them to differentiate the sizes
BLUE - 80x160mm
GREEN - 80x80mm
ORANGE – 40x40mm
BROWN – 28x160mm

The dimensions of the room that both the cnc machines will be in, as well as our needs obviously, dictated the size I chose for the table: 1400x2200mm

Having not worked with aluminum profiles before I am questioning if I might have gone a little overboard on the largest profiles. The 80x160 also comes in a “light” version, and I am wondering if they might do. Any opinions?
I’m having a meeting with a salesman from Rollco on Tuesday and hopefully he will be able to advise me a little too.

All the linear guides and ballscrews will also be from Rollco

In my preliminary design I have opted for Rollco’s Belt Driven Linear Unit for the X axis YouTube - Assembly of a belt driven linear unit RHL80 from Rollco.

It will have a timing belt driven gear reduction from stepper motor. It appears to me to be an ideal choice in regards to it being an enclosed unit, but I am unsure of it’s precision and rigidity. Anyone have any experience with this type of unit?

If it turns out the belt unit is unsuitable I am leaning towards rack & pinion for the x-axis. More work in regards to fabrication, but a tried and true system.

The y-axis is, as stated, 1400mm and here I am opting for a 20mm ballscrew with either a 5 or 10mm pitch. Possibly gearing the stepper up slightly with timing belts for higher rapid speeds.

My goal, in regards to speed, for the router is at least 10m/min rapids for the x-axis and slightly lower for the y-axis. I don’t think this is unrealistic. Any views?

Please disregard all the errors with the placement of the trucks for the linear guides… I’m working on it

Mikael

[mcentric]

My purchase list of electronics is also taking shape.

Apart from the C11 multifunction board from CNC4PC, I intend to purchase all the components, that aren’t readily available here in Norway, from DamenCNC in the Netherlands.

This list, so far, contains the following:
Teknomotor C41/47-C-DB-P, 2kW spindle ER25 collets
Delta Electronics 2.2kW VFD
PoKeys55T
PoPendant
2pc. 48V 6A switching power supply
4pc. HP5056, 5.6A 50V stepper driver
4pc. DCNC-IP54-4,5NM NEMA 34 stepper motors

Mikael

[mcentric]

A tiny digression. This is a quick walk-through of the workshops where I get to play... I mean work every day

YouTube - HiAk Workshops walk-through
Mikael

[eigstein]

with all that fine woodworking machinery at your command ,you might want to take a look at this german site. Schreinerei stefan Welschoff CNC-Wood - Home they show a large and a small machine made largely of wood .google will translate the german to english .

sincerely ,

eigstein

[eigstein]

this is a add on to the page we just posted . CNC-Wood - Home is what we typed . but cnc-wood-home is what we got ? you can get there from that adress but it is not direct.

eigstein

[eigstein]

i've just exposed my ignorance of e-mailing.

eigstein

[mcentric]

Thanks for the link, it worked fine
I considered a wood based construction like my first router build, but decided on aluminum for a couple of reasons. The machine needs to be robust enough to withstand use, and certainly abuse by the students. And, I want to be able to dismantel it into manageable bits so we can, for example, take it to education expos as a promotional gimmick. My experience with wooden constructions like my last build has taught me to keep dismantlig and re-assembly to a minimum.

Mikael

[slektning]

Du kan jo vurdere ac servo kit fra dmmtech.com

Utrolig fine komponenter og god service

[mcentric]

Originally Posted by slektning Du kan jo vurdere ac servo kit fra dmmtech.com Utrolig fine komponenter og god service

That was indeed a great price, but I think servos will be slightly overkill for this build

Mikael

the url is www.dmm-tech.com btw

[mcentric]

I've had some email correspondence with Kevin from http://www.damencnc.com today, and his service has been outstanding. He will be advising me a bit on my choices of hardware in this thread so hopefully it will be of help to others as well.

Mikael

[mcentric]

I have tried to calculate how much the router will end up weighing based on the profiles, linear guides and ballscrews I will be using. I’ve just “guesstimated” the weight of the remaining components. I've come up with the following values.
Table with legs: approx. 280kg
Gantry complete: approx. 45kg

I also had a meeting with the sales rep. from Rollco today which was very enlightening. We went through all my requirements to build the router according to my current design and I was given a very good deal. Still, my initial cost estimate has turned out to be off….. quite a bit off actually so I will need to present the new budget for approval before I move any further. Shouldn’t take long though.

Wish me luck

After a guarantee from Rollco that the belt units will meet my precision/repeatability requirements, I’ve decided to go for this option for the X axis.

For the Z axis we decided on a complete bolt-on unit with a 300mm stroke. (see picture)


For the aluminum profiles I decided to go for the “light” versions of the 80x160 and the 80x80. He had some samples of both versions, and I am positive the “light” versions are more than rigid enough. It will save me about 45-55kg on the entire build, and the cost was considerably less.

Mikael