Hi,
if you are considering high torque 34 size steppers, be careful. While they have great low speed torque they often hqave high inductance which means the torque falls
to near zero at as low as 500rpm. They are also subject to mid-band resonance. You need a machine that exhibits an inertia ratio of 2:1 or 3:1 or better otherwise
mid-band resonance will screw you.

The important spec that you need to consider when buying stepper is inductance, the lower the better.

23/24 size steppers, 1mH-2mH, 1mH preferred and reject anything over 2mH
34 size steppers, 2mH -4mH, 2mH preferred and reject anything over 4mH

Often a modest 23/24 size stepper say 400oz.in but with low inductance and therefore retain useful torque at 1000rpm, say 35% of its initial 400oz.in or 140oz.in
whereas a 34 size stepper having much higher inductance will have only 5% of its torque at 1000 rpm. So even if it had 1600oz.in initially it would have only 80oz.in
at 1000rpm, if it did not stall already! The 24 size stepper is better overall.

This runs contrary to the popular belief among new buyers, I mean high torque has got to be better than low torque right?....but sometimes no. Its all about how much
torque a stepper retains at speed, and there often a 23/24 size stepper will beat a 34 size stepper.

Craig

just question please,did you ever work with 5 axiss??
because as yours budget ,i think you not very familiar with  5axiss
there so many points you must clear about 5 axiss....(be sure you know how adjust it and have correct software and tool to adjust)
and after all this use steppere instead of servo?? for me its sound very very strange
by the way did you think also about the kinematic pp? which way you will calculate it?

Hi,
it's taken me nine years to get around to fitting a fourth axis, and I've made a start on a fifth axis. I will need to complete it fairly soon because
I have paid $2000NZD for a 12 month subscription to Fusion Machining Extensions for four and five axis and I need to use it before it expires. It's by no means certain
that I can afford to renew the subscription especially as it will be full price this time, $2700NZD! Katz is right, four and five axis is ambitious, even five axis
CAM is going to set you back on your heels without counting the hardware.

Craig

we will start our 5 axiss next week ,if you want i can share the steps how we assembly
its not simple machie because its have also second head with 9 drills ,one spindle ATC 5 axiss with 20 tools and its have auto load unload system
board size 3100*1300mm

Hi,
my fourth axis is pictured above as is the new worm drive that will become the fifth axis. The chuck will be removed from the fourth axis and a trunnion
table will be fitted in its place. I will probably use a stepper for the fifth axis to start with until I can get another servo. They cost $1000NZD by the time
they get here, so I usually have to save a bit!

The mechanical and electrical fitting are no trouble.

The real challenge will be to get the post processor to produce good code. I've had pretty good results with the rotary fourth but a fifth is going to be a step up.

Craig

Hi,
the new worm drive gearbox is at the shipping depot in Portland and I've just paid the tax and international freight......not cheap.

The gearbox cost $180USD. The shipping was $36USD within the US and another $139USD for the international shipping to New Zealand.
Thus the total shipping costs are $175....compared to the cost of the gearbox $180USD. The GST (NZ tax) is another $30USD. Anyway it is what is,
its paid for and will be here in a week or so.

Craig

Very nice
But in our work style ( wood working) the board are much big ( 1220*2440mm or 2070*2800mm)
So we don't have such option to turn the parts we must rotate the head on 2 circle axiss,this much more complex ,like keep wires ....limt the angle....etc

Hi,
I assure you a trunnion table and fifth axis is by no means simple when you have to maintain rigidity enough to cut steel and where
microns matter.

Craig

By the way I saw you don't use ATC ,in 5 axis you also can stay without ATC?

Hi,
my machine is funded out of my own pocket and so there is a very distinct limit to what I can do.

My machine has travels of 350mm x 350mm x 350mm. It has a linear resolution of 1 um and I'm trying to
end up with a machine repeatable to 10um or better. The overwhelming majority use it gets is making circuit boards
by isolation routing. It's a bit like using a sledgehammer to open a walnut I know, but its what I do for a living.
For that purpose I have an 800W 24000 rpm asynchronous spindle and I've had and used it for nine years.
I would love to be able to replace it with an ATC spindle, but trying to find one that matches the quality of my existing
Mechatron Gmbh 800W manual spindle is not easy, or rather it's easy, just not affordable!

The best replacement I can find is by the same company is an ATC 2.5kW, 42,000 rpm with an HSK25 tool interface for
5700 Euro. I just can't afford it.

As I posted earlier, I have paid a discounted $2000NZD for a one-year subscription to Fusions Machining Extensions.
I need to make use of that time, it may well be that I cannot afford to renew the subscription when it comes due in July, so I want
to use as much as I can before then. Ergo the push to use my fourth axis and the push to get a trunnion table and fifth axis working.

It must be said that I've had the fourth axis gearbox hanging around for years. I bought it thinking to put it on my mini-mill but it was
just too big and rugged for that machine. It's a perfect fit for my new (approx 18 months) mill. Even then I still had to buy a servo $1000NZD,
a chuck $150NZD and have my employee turn up the shaft through the gearbox........so even having the gearbox does not stop the drain
on my budget.

As you have seen I've bought a suitable gearbox for the fifth axis, but it cost all up, including tax and freight $614NZD. the next thing I'm eyeing is yet another
servo to drive it, another $1000NZD, and that does not count getting the steel laser cut for the trunnion table itself. I should be able to machine it all
myself unless I decide it needs to go on the surface grinder, that will cost me. All of this comes out of my pocket, and I'm just a working man so it takes
a while.

Craig