Re: [CAD_CAM_EDM_DRO] Mini Toolchanger Videos

I somewhat, kind of agree.
Based on my experiences with a chinese 7x and a heavier commercial 12x.

What where your experiences with Sherline shortcomings ?
Spindle motor overheating ?
Inaccuracies ? Thermal twist ?

Or just too slow ?

I found that I could use a 7x to do fairly good pieces in steel-
but far too slowly.
I suspect that the crossover point is in the industrial components-
retrofit which is way more expensive than the "cheapest bits- lets see
it run" level.
And when one uses industrial components, it makes little difference
whether the original base machine was 500, 1000, 1500 or 2500, when the
difference in price in each level more than doubles the inherent
productivity.

I see the sweet spot in the new, base-price approx 2000-3000 chinese
iron, fitted with appropriate linear guides, ballscrews, mounts, drives etc.
And a secondary sweet spot in fitting the same to very heavy industrial
tools in the multi-ton range, at the same base cost but capable of
producing better work at 3x the speed.
In both cases a basic cnc retrofit is 2-3000 $ in components, and lots
of work. Many on these lists have done such.

It a bit like trying to do a very, very good 9x, based on say a
Schaublin lathe.
It will be difficult to find a base machine for less than 3000, where a
new more rigid (but far less well finished) 12x is 2000 or so.
Thus, there is very little incentive to make a very good 7x or 9x,
where the 12x or so will always be far better in terms of productivity.

Having said that, I still plan to make a barfeeder for my 7x ...
In my case, it will be a demonstrator and showcase prototype for
commercial (toolchangers and one-off etc.) stuff I do.
As such, it fits in a niche where I can justify, to myself, spending
1000$ in bits n pieces for it, where the value of the product is in
being able to take it to shows and the vow factor is far more important
than the work produced.



Phil@Yahoo wrote:

>
>
> I noticed that in most of those videos the tool changer was mounted on a
> Sherline mill. I tried for a while to use a Sherline for production work,
> but found that the amount of maintenance required to keep it running
> outweighed the benefit of using it that way. I know some people use these
> machines for production work, but I think it only works well if you
> have the
> right combination of precision, complexity and price insensitivity. In
> other
> words, if you are producing something that commands a fairly high
> price but
> does not require a great deal of precision and does not have to be
> produced
> in large numbers (i.e. cost-insensitive niche market) then it might work.
> Otherwise, because these machines were never designed for continuous
> operation, the cost of maintenance and rework becomes prohibitive. Unless
> somebody is a wealthy CNC hobbyist who loves gadgets, or one of those few
> manufacturers who fit the profile, they would be unlikely to have any use
> for such a thing. Personally I think they're pretty slick, but would
> view it
> as a time sink unlikely to pay off in any way besides fun. If that's what
> you want, go for it.
>
> --Phil M.
>