G'day from central Victoria, Australia

[Plas4u]

G'day folks

I run a small plastics fabrication business in Australia and am at the point of purchasing a new CNC router. I am as near as ninepence to stumping up close to $45K for a new Matcam and have just come across this site.

For the last few years I have been making do with DIY CNC router based on a conversion we did of a manual Torque Work Centre. This is a belt driven system and we have fairly flogged it over the years and, whilst it is still going okay it is nowhere near robust enough for task at hand. Plus it does not quite handle a full sheet size.

This of course has led me to the decision to upgrade to a commercial system. The problem is that $45K is a lot of money for a small business and it is hard to make the decision for such a large commitment.

Having seen some of the incredible builds by members of this forum I am considering the Mechmate as a viable and more cost effective alternative. The fact that getting a new machine from the States takes 3 months means I may be able to get one built in a similar time frame (I hope!). I may even outsource the building of the frame as I wont be able to run my business and dedicate enough time to handle a complete build.

So before I pull the trigger on buying the plans I am hoping I can ask a few questions first.

Firstly, I notice that the table frame of the Mechmate is quite elaborate and possibly the most time consuming aspect of the build. When I see details such as the mitred beams I am wondering is they are just for ascetics and if so why more builders are not just leaving them square to save time?

Secondly, I am wondering if the instructions give details of the rack and pinion system such as the required pitch for an 8 x 4 table?

I am pretty handy but not terribly technical so , essentially, is a nong like me going to have enough nous to understand the technical details required?

Any encouragement and words of wisdom would be greatly appreciated.

[Plas4u]

Oh, another question I forgot. A vacuum table is vital for me. Does the Mechmate design allow for the addition of a torsion box top to which I can add a vac pump. I assume I can just make the gantry a bit taller to accommodate a thicker top.

[darren salyer]

Welcome to the Forum, Iva.

The plans are very complete. Things like the miters you speak of only add minutes to the build and help to create a more refined machine in the end. The decision on how much effort to put into the machine is surely yours to make.

A torsion box top really isn't not required for vacuum. Two layers of MDF with a grid in one for a plenum is all that's necessary.

In any event, height above table is best controlled by height of your main side beams than gantry mods.

[pblackburn]

The main beams do not need to be cut angled or capped. I did not and left them a square cut however it does make sense for the idea of whacking your head on it to not cut it. I only used a air sander and rounded every cut edge to prevent cuts. The down side of closing it is it is a dust trap. It does have the potential for stiffening the channel but I can say that I hold extremely tight tolerances with the the ends uncapped.

[bradm]

Angling the main beams can add a few inches of capacity. For example, if you are building a machine for 8' sheets in the US, a single "standard sized" 20' piece of channel can be used to create two angled beams longer than 10' for a cost savings.

The time spent on the angled cut and cap is inconsequential in the overall steel work, and will be endlessly grateful for eliminating sharp points at the corners of the machine once you start loading and unloading it. As Pete notes, at least you want to round the edges.

[Plas4u]

Thanks for the responses. Another aspect that struck me a overly time consuming is the guide rails. It looks to me that these are lengths of angle iron of which one side is cut down and then ground to a bevel to accept V bearings.

Some builders have mentioned hours of work in this step and I can see the potential for inaccuracies. Would it not be simpler just to bolt on shop bought linear guide rails to the side beams? Would this be possible or would it upset other aspects of the design?

[pblackburn]

Each poses its own planning and understanding of the concept. If patience is taken, grinding the rails is not hard. I opted for a hardened v-rail bolted on to move the wear surface from soft angle to the v-wheels. I had the v-wheels hardened to 40-45 RC to extend the wear and life of both.

The linear guide question comes up quite a bit but the truth is the V system has many advantages when it comes to dust and debris. It creates a natural wiping action that removes the debris from the path. Grease on the other hand naturally attracts it.

[KenC]

Iva, what have you gotta lost with only around 10~20% of the 45K?
Just Whack 1st, ask questions later.

[lonestaral]

Welcome Iva.
The build that you end up with is up to you.
My machine is not the biggest, best looking,fastest or the most accurate on the forum.
Having said that,I am very happy with it.

Treat the plans as a map.
There are many paths from start of build to finish of build.
Quick, short, cheap, expensive , scenic to name a few.

If you sub out the frame for fabrication you might as well have the angled and capped ends.
As for the rails, everybody worries about them.
No big deal, just dirty and noisy.
Dont know what you will pay for v cap rails.
Again the choice is yours.
Welcome and enjoy your time here.

[Plas4u]

Plans purchased so it is into the abyss of general ignorance I go. Wish me luck!

[darren salyer]

Good Luck!!

[racedirector]

You'll do fine Iva. If I can build one with minimal tools you could too. It all seems daunting at first but taking it in small chunks is the way to tackle the monster.

[Rapid]

I just received my laser kit a few days ago and have been on this forum about two weeks. You will quickly gain confidence if you read read read and study the plans and look at the photos in these build threads. When I first opened the laser kit I admit I felt a bit overwhelmed. Read and study and the confusion will soon dissipate.

Now I am gaining confidence and looking forward to the build.

The laser kit is a good deal ... all of the difficult parts are precisely made for you.

I suggest you keep reading until you start gaining some confidence. Also you need to have your business under control so that you will have adequate time to do the build.

I have some tech school training in cnc. If I did not have this schooling I know I would be totally lost here. But others do the build and then teach themselves to operate cnc. It is going to take time and dedication and it will be frustrating at times. Good luck

In the end a cnc machine might be exactly what you need to make your business thrive.... and if so then all of the effort will be worth it. Also gives you a great sense of accomplishment.

[Rapid]

Iva I just want to comment that it is unfair to compare the $45,000 machine you mention in your OP to a MechMate.

MechMates cost about $6-8,000 for materials plus your time. MM's replace factory made machines like EZ-router and Shopbot and those machines cost about twice what a MM will cost you for materials

.... so is your time worth $6-8,000 US dollars ? .... if not then you might consider buying an EZ-router or Shopbot.


Hope my advice is helpful in your decision making.

[Plas4u]

Thanks for your thoughts Rapid

As I mentioned in my OP I have a CNC router on which I am heavily reliant so for me it is a question of upgrading rather than a new foray into mechanised cutting. The machine I have is not robust enough and I really should be using a commercial grade machine.

Having said that, the results and through-put I see people getting out of their MM is more than adequate for what I do, hence the thought that I may be able to save my business of a fairly hefty leasing cost each month. This was the decision I took when I had my first CNC commissioned - better to have a $5K machine that you own outright sitting idle rather than a $60K machine that you have to feed with cash each day just keep it in your possession.

My only hesitations with the MM build is firstly time as I really do not have the capacity to take on a project of this size at the moment and secondly my electronics skills are nil (which frightens me a bit- actually a lot).

So if I take on this build the advantage is that I get to learn a new skill and will no longer be reliant on others to fix my machine when something goes wrong. I also get to be in a more comfortable financial position without the worry of having to stump up leasing costs month after month for 5 long years.

You blokes in the States are spoiled for choice when it comes to equipment at good prices. In Australia we pay through the nose for everything.

[pblackburn]

Iva, in all fairness, most of our stuff is made in China now so the quality is also suffering.

[Plas4u]

The thing that is getting me all hot and sweaty is the wiring etc. I have read lots on the forum about wiring but much of the language used is Greek to me.

On the subject of selecting motors I note that Gerald suggests a certain geared motor from Oriental. I have not been able to find them available in Australia but I have found Nema 34/625oz.

The CNC I have at the moment has some pretty rough wiring (no control box, heat sink, push buttons, limit switches or anything fancy) but it does seem very simple and I am wondering if I can copy this (perhaps neaten it up within a control box)for use on the MM.

What I have at the moment is the following:

1. S600-48 powersupply
2. Gecko 540 4 axis control board with built in BOB
3. FRA8PC-S2 DC 24V (I assume this is a relay?)
4. 4 off 24H290-28-4B MS Stepper motors.

My X axis has 2 motors and the Y and Z one each. Each of these motors plugs into the G540 and a parallel port cable goes to the PC. The relay is doing something but I am not sure what. An simple rocker on/off switch is wire to the power supply and that is it.

It seems pretty simple and at odds with the seemingly complex setup I read about as a kitchen table exercise.

The spiel on the Nema 34's says they will work with a G540 if they are wired in series. What does that mean?

Are Nema 34's a good choice? What are other Aussies using? Can I use a single G540 rather than separate Geckos for each motor?

The G540 almost looks plug and play but I am guessing you need to do something on the software side to set it up. Good lord, where do I start?

[KenC]

Are you aware of the size difference between you CNC & MM?

[pblackburn]

NEMA 42 are becoming very hard to get. Maybe not on that side of the globe but in the US a lot of MFGs are going away from them and leading you toward the NEMA 34 with gear reduction of some sort. I would recommend belt reduction and not gearbox unless planetary or harmonic.

The G540 specs look too have a lower limit (top end) on the voltage and current. 3.5A is limiting yourself before you start.

[racedirector]

Aussie chiming in here..

I went with 640oz-in Nema 34's from AusXMods in Aussie. They are non gearbox motors but reduction drives are easy to build from either kits available or DIY once you have the machine running.

For controllers alot of guys go for the Gecko 203Vs or some go for Leadshine Digitial controllers, for example DM856 or AM882. I went with the AM882 due to the alarm functions on them and got them for less than buying the Gecko 203's. China is your friend in this case. The G540 is more targeted at smaller machine typically running Nema 23 motors.

You can also chuck an Ethernet Smoothstepper or equivalent into the mix if you have a PC without a parallel port. These remove the task of communicating with your mahcine away from the computer itself and on to the ESS board.

You would also need a breakout board to connect your PC to the motors/controllers, PMDX versions are one of the manufacturers people go for. The PMDX 122 was my choice, some use the PMDX 126.

Non regulated power supplies are better suited to our environment, they can either be bought ready made or again DIY'd from a toroidal transformer, some capacitors and a bridge recitifier.

The MM is basically an industrial level machine and therefore requires bigger equipment than you have now. Judicious buying from overseas and DIY'ing as much as possible can save some big dollars and give you a better feeling than having someone else do the work. The more you do yourself, the better you will know your machine if it ever breaks down.

Cheers

[KenC]

Regulated power supply is not suitable for driving motors. Regulated power supply is like driving a car with one foot on the break 100% of the time.
Use unregulated power supply with simple transformers (either EI or toroidal) + rectifier + capacitor. Its simple, it has lowest possible source impedance (which means ultra fast response) . the free bonus is once done, it will last until the capacitor dries up which is a life time for me.
Stepper motors will work just fine Even with +/-20% voltage variation. As long as its within your stepper motor driver voltage limit.
Seems like you are working on your reading chore Keep up the reading, 99% of your questions will be answered.

[Rapid]

Iva your knowledge of electronics is equal to mine... Keep reading.... this thread is already teaching me more about the electronic side of the build. Buying a manufactured machine will cost a lot to ship. You buy the large heavy steel locally and the shipped parts will come in small boxes. I suggested $6000-8000 saved by building yourself but I had not factored in the cost to have a machine shipped to your location. That cost is an additional saving.... which might actually cover the cost to pay a fabricator to build your table.

I am using Linux and I have downloaded and printed out the instructions for setting up the control.... they are step by step easy to follow instructions.

[bradm]

The G540 is a very good match for the Oriental Motors with gearboxes, because that specific motor / gearbox combination does not need more than 3.5A to operate well - the motors are rated at 3A, and the torque comes from the gearing.

That motor / gearbox is a little unusual though, and most other Nema 34 motors can utilize higher amperages to advantage. The G540 + PK296A2A-SG7.2 combination gets you 4 motors, 4 drives, and a BOB for about $1,350 here in the US.

My understanding is that the Gecko products are more difficult to obtain and expensive elsewhere, so you may be better off with a different combination.

[Rapid]

Iva if you build a MM will you sell the smaller router or keep it for backup. If you keep it maybe you could swap over the gecko 540 and computer and just buy the geared steppers. Limit switches are cheap and easy to wire.

I think we are trying to talk you into going for it

[Plas4u]

Thanks for all the positive responses. Without question you are all right, this forum is an amazing resource and all the information I need is here (somewhere). However, for me, the forum is a series of rooms within rooms. The more I look the more lost I get.

Notwithstanding the fact that everyone will have different needs, different budgets, different amounts of space etc, I still would have thought that there would be a more straightforward and easy to follow recipe that having to wade through so much diverse and confusing information.

After all, the MM is billed as a sheet cutter. Most sheets come in standard sizes depending on where you live so I was hoping for instructions that simply said "if you want a table to cut 2440 x 1220 sheets up to x thickness at x m/per minute then you need to build a frame x big, use 4 of these motors with these drivers, using this powersupply. Buy x metres of this rack and 4 of these pinions............etc" .

I am just not going to be able to juggle running a business full time and playing detective at night trying to piece all this together.

So, as a final question before I chuck in the towel, is there any shopping list, any formula, any step by step plan I can use and simply follow to build a table to cut 2440 x 1220 sheets (plastic, wood and composite aluminum) varying in thickness from 1.0mm to 30mm?

[pblackburn]

What you are asking is all included in the plans. You have your dimension there, so plug them in and calculate your BOM. A shopping list is as you said dependent on the builder and their needs. What I need is not necessarily what you need.

[Plas4u]

Thanks Pete

I must have downloaded the wrong plans then. On what page does it tell me what size and brand of motors to buy? Where in the plans is the recommendation for which Gecko drives to use? I found pictures and drilling details for the rack but are all racks the same?
I think I am out of my depth

[pblackburn]

The motors, drives and electronics are more of a personal preference than a set in stone 'you must use this.....period'. That would not be on the prints. Most say the Gecko 203V is a near bullet proof drive and oriental makes a great stepper. Any drive will run a stepper that is sized to it. You had some great advise given in the previous posts. This was left in the air intentionally in my opinion as what is available in Europe is not available readily in Africa, and the USA, and Australia and the Netherlands, etc.....

What you are experiencing is from trying to jam too much into your brain at one time and trying to force an outcome.

On the prints, the cover should have a contents section that lists the print number and the title. No they are not all the same. I would recommend printing out the plans and separating them into their distinct sections, base, gantry and y car.

[Plas4u]

Thanks for your patience Pete and I do realise I am being a pain but it is borne out of frustration.

Just so you appreciate the simplicity of my thought process I am hoping for someone to say, "hey, I built an MM that cuts 8' x 4' sheets. Sounds like what I have is exactly what you need so these are all the parts I bought to build that table".

A machine that cuts 8' x 4' sheets with nice clean edges to a tolerance of .001mm is all I need.

If anyone has built such a beast please tell me what to buy.

[dbinokc]

One micrometer tolerance! I hope you just accidentally added an extra zero or maybe meant .001 inches.