Choices, Choices

[Stewbaru]

Hi All,

I am new to the forum, and new to CNC in general.
I am cad based drafting with basic CNC orgrammng skills and I will be setting up a workshop at home. I am looking for a 4 axis machine, for working aluminium, and steel to 1/4" with a 1/16" cut.

Currently in Australia, I reckon I have two choices of Mill:-
1. The Taig - http://www.taig.com.au/index.php?mai...roducts_id=429
2. X4 Plus - http://www.syil.com.au/product_X4Plus.php

It looks like the X4 has more whistles and bells , is this a good thing?

NB: The taig I can get for about $4.5K (5.1K with 4th axis)

Do any of you use either of these?
Which is the better start-up machine, pros - cons?
Any advice you can offer is appreciated....

Thx in adv,

Stew.

[Adamj12b]

Just a quick piece of advice, Get the largest machine you can afford. I Bought an X2 and am wishing that I bought the X3. The X4 is quite a bit larger then the Taig, And I dont think that you would regret it. I know that I wouldn't. Just my 2 cents. -Adam

[Stepper Monkey]

Two things I can add;

First, you should be able to find a complete Taig setup for closer to half that amount, if not over there then shipped in from the US. There are good and bad ways to do it as regards reducing/eliminating the duty, if you need help with that we can advise.

Second, Even though they have comparable cutting areas, the X4 is a HELL of a lot bigger, heavier and more capable of bigger cuts than a Taig, so if you can afford it just go that route unless you really know you'll only ever be doing lighter workpieces or you require the compactness and/or portability.

[philbur]

Biggest is best has to be qualified.

The Taig has a spindle sped of 11,000 rpm the X4 3,200 rpm. This will make a big difference if you are using lots of small diameter cutters.

Phil

Originally Posted by Adamj12b Just a quick piece of advice, Get the largest machine you can afford. I Bought an X2 and am wishing that I bought the X3. The X4 is quite a bit larger then the Taig, And I dont think that you would regret it. I know that I wouldn't. Just my 2 cents. -Adam

[Stewbaru]

Originally Posted by philbur Biggest is best has to be qualified. The Taig has a spindle sped of 11,000 rpm the X4 3,200 rpm. This will make a big difference if you are using lots of small diameter cutters. Phil

Phil, you mean the Taig's higher speed will be better for smaller radii and fillets?


Stepper, "reducing or eliminating duty"? means what to me and a taig?

Sorry to be a newbie, but I am....

[Stepper Monkey]

Originally Posted by Stewbaru Phil, you mean the Taig's higher speed will be better for smaller radii and fillets?

Higher speed means you can use smaller cutting tools for detail work, circuit boards, modeling, engraving, etc. Things a big mill can't really do well. Proper RPM and feedrates for tools are very important, and one of the defining features of small tools are very much higher speeds they have to spin at. If you are planning on using, say, 3/8" or 1/2" diameter mills to really remove material you will be using the slow spindle speed ranges of the heavier machines.
To run smaller bits, especially 1/8" and below, you absolutely need much faster spindle RPM's and a very much lighter headstock and lower mass of a smaller machine.

Some people, generally those who never cut small parts, will say that you can cut a small part on a big machine but you can't cut a big part on a small machine. That is only about half right.

To cut small parts at all effectively you really do have to use a light machine.

Cutting really heavy materials on a Taig is slow and time consuming, and with mixed results. It really excels at very light to medium work.
Cutting small, fine detail work on an X4 is frustrating and expensive at best, and also with mixed results. It really excels at medium to heavy work.

You need to define what you are going to be doing to determine the best machine to use.

Originally Posted by Stewbaru Stepper, "reducing or eliminating duty"? means what to me and a taig?

Duty - as in tariffs or import taxes or whatever you call them. Depending on how something is categorized you can get hit for a little or a lot, and sometimes nothing at all. If you don't know the right bureaucratic numbering nonsense to put on the package they can want an arm and a leg in taxes when you go to pick it up!

[philbur]

So Stew now Stepper has brought us to the question you should have asked yourself in the first place. What am I going to use it for.

A 14 lb sledge hammer is good for breaking rocks. A 4 oz pin hammer is good for cabinet work. Each is not very good at the other. Before you pick the tool analyse the job.

Phil

Originally Posted by Stepper Monkey Higher speed means you can use smaller cutting tools for detail work, circuit boards, modeling, engraving, etc. Things a big mill can't really do well. Proper RPM and feedrates for tools are very important, and one of the defining features of small tools are very much higher speeds they have to spin at. If you are planning on using, say, 3/8" or 1/2" diameter mills to really remove material you will be using the slow spindle speed ranges of the heavier machines. To run smaller bits, especially 1/8" and below, you absolutely need much faster spindle RPM's and a very much lighter headstock and lower mass of a smaller machine. Some people, generally those who never cut small parts, will say that you can cut a small part on a big machine but you can't cut a big part on a small machine. That is only about half right. To cut small parts at all effectively you really do have to use a light machine. Cutting really heavy materials on a Taig is slow and time consuming, and with mixed results. It really excels at very light to medium work. Cutting small, fine detail work on an X4 is frustrating and expensive at best, and also with mixed results. It really excels at medium to heavy work. You need to define what you are going to be doing to determine the best machine to use. Duty - as in tariffs or import taxes or whatever you call them. Depending on how something is categorized you can get hit for a little or a lot, and sometimes nothing at all. If you don't know the right bureaucratic numbering nonsense to put on the package they can want an arm and a leg in taxes when you go to pick it up!

[hoss2006]

Proper RPM and Feedrates are important and so is knowing WHAT they should be.
You can check any industry standard calculator or chart out there, such as this one, to see that
11,000 RPM (Taig max) is the recommended RPM for a HSS endmill no smaller than .209 inch for aluminum or plastic.
Recommended RPM for a .125 endmill is 18,335. A 1/16 endmill needs 36669 RPM.
Carbide tools would double these RPM's if you want to use your equipment properly.
Makes the need for an addon High Speed spindle obvious.
The Air turbine spindle we use on the Matsuura at work tops out at 75000 RPM
which matches it to the 1/32 endmills used on occasion.
There are plenty of electric models that could be used on the X4 if you need to delve
into the circuit board, engraving areas.
Just something to keep in mind.

[Stewbaru]

Phil, Generally I will be using it for RC parts for 1/8 and 1/5 scale buggies.
Material of choice will be 6-10mm (1/4 - 3/8") 6061 or 7075 aluminium. I may dosome plastic, but not alot.
Component size will be at best 150mm - 180mm x 60-70mm unless I start doing chassis plates (these can be up to 400mm long. a stretch for the taig)
I will also be looking at circular machining for bead locks and possibly billet wheels (these I know will be slow).

I don't reckon I'll be doing circuit boards.

Basically, I want to tool around in my shed on weekends for fun, this project is not cash motivated.

[Stepper Monkey]

Since it is for fun and therefore production speed isn't critical, you could get away with either one just fine. While both can do the jobs you describe, it sounds like the X4 is the best suited to your needs by far given a choice of the two as it has the power for not only doing it faster but offers a lot of other extra capability as well.

If you want to do any stuff with wheels you will absolutely need a rotary table. You won't necessarily need a big or expensive one, but you will need one.

[ToolMach_Aust]

Stepper...

The X4 can also do very light work with great accuracy .. it does have Double ball nuts.

The X4 can travel at around 6000mm/min with accuracy of 0.01mm or better... a lot of people are adding a High Speed spindle to the X4 to do the high speed machining you are talking about.. with a HS spindle on the X4 you can do everything and more than smaller lighter machines... Smaller machines are really only good for plastics or other soft material.

The point is it is comparing Apples to Oranges...

cheers

Frans

Originally Posted by Stepper Monkey Higher speed means you can use smaller cutting tools for detail work, circuit boards, modeling, engraving, etc. Things a big mill can't really do well. Proper RPM and feedrates for tools are very important, and one of the defining features of small tools are very much higher speeds they have to spin at. If you are planning on using, say, 3/8" or 1/2" diameter mills to really remove material you will be using the slow spindle speed ranges of the heavier machines. To run smaller bits, especially 1/8" and below, you absolutely need much faster spindle RPM's and a very much lighter headstock and lower mass of a smaller machine. Some people, generally those who never cut small parts, will say that you can cut a small part on a big machine but you can't cut a big part on a small machine. That is only about half right. To cut small parts at all effectively you really do have to use a light machine. Cutting really heavy materials on a Taig is slow and time consuming, and with mixed results. It really excels at very light to medium work. Cutting small, fine detail work on an X4 is frustrating and expensive at best, and also with mixed results. It really excels at medium to heavy work. You need to define what you are going to be doing to determine the best machine to use. Duty - as in tariffs or import taxes or whatever you call them. Depending on how something is categorized you can get hit for a little or a lot, and sometimes nothing at all. If you don't know the right bureaucratic numbering nonsense to put on the package they can want an arm and a leg in taxes when you go to pick it up!

[Stepper Monkey]

with a HS spindle on the X4 you can do everything and more than smaller lighter machines... Smaller machines are really only good for plastics or other soft material.

People keep repeating that a lot, but it still doesn't make it true. Big machines are certainly more flexible, but there is a reason there are different sized machines out there, and it isn't just space or cost. They have different purposes, and there are things that can be done in hardened steel with a machine no bigger than an X4's head casting that you just can't attempt with an X4.

No matter what an X4 has for max XY table travel speed or accuracy, it doesn't have the accel, especially on Z. The Z head mass and screw/motor setup stops it from being at all useful for much small high-detail cutting, and hanging yet more mass on it with a side-mounted high speed spindle makes it even worse.
Hoss was right in that you can indeed use this type of setup on a large mill for engraving and circuit boards just as well on a big machine as a small one. Those two specific jobs don't require the Z to do much obviously, not during a cut, and thats the real limit. For those things a side mounted spindle will do fine, and it is a useful thing indeed. Much of the rest of the very broad range of very small cutter/high speed work can't be done well on a big machine. Much of it can't be done at all. Period. Physics make it impossible. There just aren't two ways about it.

Sometime soon here I will post a detailed explanation of what makes a machine work for cutting in that range so you guys can better understand. It makes very simple, intuitive, and very plain sense once you look at it, but unless you do this kind of work a lot there are a bunch of things that you wouldn't normally think of right off. Trust me, its not rocket science. One I put some of it out there I'm sure you'll agree.
It is a very, very different perspective from normal machining and many design factors that normally make for an excellent machine for normal scale work can be serious disadvantages or a complete killer at small scale.