Looking for information to help buy my first CNC machine

[mholt1985]

Hi All, Im looking for a little help in deciding which machine to go for, or the benefits of each,

Im a graphic designer looking to branch into 3D Plaques, signs, memorabilia and prototypes.

Im looking to machine in wood and plastic, and if the Machine could cope with metal then Im sure I would find it useful.

And hopefully a machine that will cope with at least A3 media.

My budget is sub £1500 for all the equipment needed, although if its possible to acquire a good quality machine for less than £1000 then I would prefer that option.

Im looking to machine in wood and plastic, and if the Machine could cope with metal then Im sure I would find it useful.

I have looked at the CNC 6040 in both 3 and 4 axis, my understanding is that X is left/right, Y is Forward/Backward, Z is Up/Down. Therefore Im assuming the 4th axis will help with 3D objects and prototypes.

4 Axis 6040 - £1390 - http://www.ebay.co.uk/itm/4-AXIS-CNC...ht_16280wt_989

3 Axis 6040 - £1210 - http://www.ebay.co.uk/itm/CNC-6040-R...t_15750wt_1079


I have also looked at refurbished machines, the one below requires Software and Interface & Driver Kits, which adds a further £350 from the same seller.

3 Axis MDL-2-TR-UN - £414.50 - http://www.ebay.co.uk/itm/2208824641...#ht_946wt_1079

Which software do you advise? is mach3 any good? or are there better options for a similar price?

Is it best to buy separate kits or ready to use kits?

My apologies for the number of questions, unfortunately the number options is so extensive Im running round in circles not knowing enough to make a decision.

Finally as a budget machine what are opinions of the below option? are there any better options you know of?

3 Axis 3020 - £508 - http://www.ebay.co.uk/itm/1406250330...t_27707wt_1079

Thanks for taking the time to look, I really appreaciate any help you may be able to give.

Kind Regards
Martin

[JAZZCNC]

Ok i'll shoot first.!

The first 2 machines look ok at first glance and they are in some ways. . . BUT! . . . Now first let me say I don't have any hands on experience of these 2 machines but I do have expereience of machines that have been or are built in similair ways so I'll just point out the areas that would concern me and leave the rest to you.!

1st: It looks like it use's un-supported round rail which is not very good choice and prone to flex greatly reducing accurecy. . . . BAD very very BAD.
2nd: The gantry doesn't look very ridged and considering it use's un-supported round rail and the not so clear or close photos I imagine they just fasten into the sides which won't give much stabilty again allowing flex. . . .flex is bad and the weak link in machines like this.
3rd: The ball screw mounting in the gantry side looks a bit jubious and again I suspect not the best implimentation.
4th: They give little info on the control box and the components it's made up with. Again I suspect it will be a weak area and very probably using cheap all-in-one 3/4axis drive board. This is ok until problems arise then you lose all drives and your screwed unless your into electronics and can replace chips etc.
The control box or should say drives and breakout board etc are the heart of the machine and if weak or cheap they will fail sooner or later or cause much heart ache in other ways like missed steps or other mind numbing issues.
5th: Bit less of a issue but still possible.! The vfd is a weak cheap chinese make (Huansang) and an area I've had personal trouble with and wouldn't recommend. That said to be fair theres folks who have them and they are ok but like I say something to be aware off.
Also the Spindle is only ER11 which will restrict cutter selection to 7mm shanks.

Personally (and unfortunatly something I come across too often) I think they look ok to folks new to cnc because of the spindle and ali construction etc but if you look closer some important areas are skimped on and to be honest not easily corrected without major work. Often this is not realised by folks with little experience untill the machine is bought and it won't do what they want or perform upto expectations leaving them very disappointed.

Like most things in life you get what you pay for and really that applys to cnc to some degree as well.

Regards the Other MDL model I won't even go there.!!! . . . But I can put you intouch with someone who wll tell you every short coming of it if you have time or really feel the need.!!

[m.marino]

The two Chinese models I have questions about as something does not seem right about the way the bearings are set up on the rounds rails. As far as the MDL router, contact me off list and I will talk to you about my experience with them. Repeatability is the key point and a hard lesson to learn. I was where you are three years ago and will gladly offer any information I can to help you on your way to a wonderful learning experience and hopefully avoid some of the traps I fell into.

Michael

[tumutbound]

I have one of the 6040 machine you mentioned. Still in the process of getting it set up
Mechanically it's OK. A few rough edges to construction but nothing major, The controller is very basic and in my case, had a bad driver for the X axis. Spare boards are available but it's a pain to have to source one and install it, especially in a brand new machine. Forget about warranty as it will require that you send any faulty item back to the seller and to pay shipping on the replacement - not cheap!
The only thing I have concerns with the machine is the limited Z travel, only 70mm or so. You may want to consider this if larger (thicker) items are to be machines. This also limits the size of items that can be used with the 4th axis
I'm considering a 4th axis for mine as it will help offset the freight cost of buying a new driver board.

Due to the dead driver, I haven't been able to fully test it. As I have a Gecko G540 controller I'm going to use it instead of the controller supplied.
It's not a good time of year though to be tracking down the necessary bits and pieces I need, everything is shutting down for Christmas.

[JAZZCNC]

I have one of the 6040 machine you mentioned. Still in the process of getting it set up
Mechanically it's OK. A few rough edges to construction but nothing major

You may think that now but come back in 6mths and report on how it performs.! . . .I'll have a small waiger you don't think it's so mechanicly OK then.:whistling:

Defiantly dump the supplied control box if you have G540 it's a fantastic bit of kit.

[tumutbound]

You may think that now but come back in 6mths and report on how it performs.! . . .I'll have a small waiger you don't think it's so mechanicly OK then.:whistling:

Defiantly dump the supplied control box if you have G540 it's a fantastic bit of kit.

If you have practical experience with the 6040, what areas do you see problems with? I don't expect it to be a particularly fast machine, given the testing of working axis I done so far, but sufficient for what I want to do. Any feedback is most welcome.
The VFD supplied with the spindle is not great with quite a few users replacing them with a name brand unit.

I've gotten most of the bits I need to set up the G540 but need to pick up some suitable cable for the steppers, hopefully tomorrow or it will be sometime in the new years before shops are open again.

[JAZZCNC]

If you have practical experience with the 6040, what areas do you see problems with? I don't expect it to be a particularly fast machine, given the testing of working axis I done so far, but sufficient for what I want to do.

Like I said in my first post I dont have any hands-on experience with this exact machine but I do have plenty of experience of similiar built machines. Mainly because I end up helping those that bought them to either fix them or replace them with better design and components. Often selling and replacing with a new machine because it's cheaper and easier.
Unfortunatly I see too often people buy these type machines thinking they are better than they really are only to be sadly disappointed. This was my main reason for posting to make aware the not so obvious and just hopefully make them stand back and look a little closer.!! . . . . When on a budget and new to CNC machines it's bit like looking at Women when you have the goggles on.? . . . .Man do you regret it in the morning.:confused:


The problems don't tend to be speed related, thou it does affect feed rate to some degree. It's more poor design and mechanicly related to do with the un-supported rails and flimsy build of the gantry and Z axis. They tend flex and twist, this only gets worse as the new-ness wears off. How much is hard to say and like you mentioned will greatly depend on the Type of work and material you work with.
What I would say is if you have need for high accurecy and desire to cut harder materials, Ali, brass even some of the harder woods then prepare to be dissapointed and work very very slowly.

[boldford]

Perhaps the panel would like to express their view on how these machines would handle Sika modelling board. I'll be more than happy to exchange notes with the original poster as I'm seriously thinking about one of these machines.

[JAZZCNC]

Perhaps the panel would like to express their view on how these machines would handle Sika modelling board. I'll be more than happy to exchange notes with the original poster as I'm seriously thinking about one of these machines.

It won't have any trouble at all handling modeling board from a mechanical strength point. Where it will struggle is with obtaining the correct feed rate to give best results IE Finish and tool life with some materials.

With only a 5mm pitch screws and I would hazard guess an under sized power supply along with crappy drives mixed and compounded with other aspects of the design and build quality then you'll be under 4mtr/min of usable cutting speed (Not to be confused with rapid feed). Which for most plastics and softer materials, even most woods, would be considered on the low side for feed rate. Cutting too slow will give a poor finish resulting in edge burning on some materials like balsa wood or thin ply plus greatly shorten the tool life.

This is where so meny new folks fall foul and don't see the potential problems with machines like this.! They think because they only want to cutt soft materials it won't be a problem.?
The reallity is that soft materials often need high feed rates for reasons stated earlier and these machines struggle to run at these high feed rates.
If pushed to run at there max they wear out very quickly drasticly reducing the machines life. The quality and accurecy is reduced because the poor gantry design can't handle the high lateral inertial loads without flexing and basicly they are just not built or spec'd to do the high feeds required.

My experience is that those that buy this type of machine while at first think they are ok but soon start to realise there down sides resutling in several different out comes.
1: Struggle with it, working around it's limits and bad points untill it becomes so annoying or restrictive they build/buy there dream machine.
2: Struggle with it, working around it's limits and bad points untill it becomes so annoying or restrictive they try to upgrade it and blow even more money trying to turn a sows ear into silk purse. (never achieved)
3: Instantly see it's bad points and get rid (Often they've had a little cnc experience before but got caught trying to take the quick cheap upgrade route)
4: Don't realise and just think cnc rubbish and either go back to the old way of doing it or give up on it all together.
5: Don't realise blissfully unaware producing crappy work and burning cutters up thinking thats just the way it is.!! . . .Untill one day they see a good machine strut it's stuff and then penny drops or they realise it's not them doing something wrong.

In most all cases they are well pissed off in the end.!!

[boldford]

Your obviously unimpressed with these far eastern machines. What would you recommend for a similar sized machine where the budget is limited