[joeavaerage]

Hi,
that makes sense, a lightweight high speed machine.

My machine is bigger and heavier and less amenable to the technologies that you want to use.

You've got to say that ballscrews mechanical advantage sure is a boon to high thrust but at the expense of speed. Having said that I can personally guarantee that
when you dial up 400 to 500 mm/s it'll scare the s****t out of you! It sure did to me.

My machine has a X travel of 350mm, and the X axis loaded with fourth axis and vice is 200kg. It can accelerate from stopped up to 416mm/s, then decelerate to stopped at the far end
of the axis then return back to the start of the axis again attaining 416mm/s before decelerating to stopped in 2.96 secs. You have to tie the machine down or it lurches all over the place.

Craig

[Mr-MaW]

The heat conduction is 1 / 20 of the cast iron, the specific heat capacity is 2.1 times of the cast iron, and the temperature change is one of the main reasons for the change of machine tool precision. The machine tool parts made of mineral casting have very high specific heat capacity and low heat conductivity, which can control the change of machine tool precision caused by the change of temperature to the minimum, and ensure the stability of machine tool machining precision.
Mineral castings

[Mr-MaW]

Mineral castings

[Mr-MaW]

https://grabcad.com/library/new-mate...ral-castings-1

[ardenum2]

Started work on the direct collet spindle. To get the same functionality like with long toolholders, I looked at hsk toolholders with long necks and integrated it into the spindle shaft. Lots more research to be done.

*How to mount the drawbar to the shaft. I've seen some screw in, some ott jakob drawbars don't even have a thread, no idea how those work.

*Figure out shaft end geometry for the unclamp cylinder, the cylinder needs to engage the drawbar but not push against the bearings.

*Air-oil lubrication channels for the front bearings, preferably inside.

*Thermal management for shaft growth

I worked on an hsk40 spindle a year ago. That was maybe my 10th go at designing spindles, had lots of educating talks with mactec at the time. Every single time I had issues wirth fitting enough spring discs inside, last design I hit 4000N perfectly within the given spindle length (thanks to the hsk40 collet being very short vs. bt30 collets from previous designs).

This time I have too much space for them! (that's not the full length on the picture)

[ardenum2]

Is it me or did image compression get way worse...

[Mr-MaW]

UHPC vs EG

To those buying uhpc from https://www.moertelshop.eu once you buy all the required additives, shrinkage reducer(which is a must) PCE etc. you end up at about the same price as EG. So make sure you know what you're doing because it's not cheaper as durcrete price list would have you think.

Here's what the final machine will look like.

I had to abandon building it on a 1200x800x120mm granite plate. The weight of the thing was 350kg and I do not want to risk having it brake in half if the guys drop it while transporting it to the 2nd floor, one guy slips and its over.

Moving from aluminum inserts to steel. I wanted to use aluminum plates and glue them with moglice to the blocks initially but once I computed how much of it I'd need I had arrived at the same cost as steel inserts.

I will use marking blue, a 4um straight edge and a hand grinder to get the inserts to desired flatness without a reference plate. If that won't work(as in takes too much time)I'll get a 800x500 granite plate as both the bed and reference. Fingers crossed I won't need it. Regardless, the bed will be 2 piece. Not sure about the front mounting plates on the bed yet.

Size 25 rails, narrow carriage CG series from hiwin(same price as HG but load and stiffness rating of RG), size 20 or 25 ballscrew with 5 pitch. Travels 420X 280Y 280Z. Total weight approx. 600kg

anyway have a look yourself : https://www.mediafire.com/file/emc1d...ca/be.stp/file

That's what I thought.
A large part of the reason why mineral castings can finally be accepted by customers is cost.
So in 2013 I started thinking about how to control costs.Thankfully, I've learned how to control costs in many ways, so price isn't an issue for me.
First molds, from the earliest steel, to the present wood (wood and steel mixed).
Own stone factory and get qualified stones.And so on, a lot of work has been done.
I also made a very bold attempt to build a gantry machining center milling machine. 6m*3m*0.8m,
If you have a good product, we can discuss it together.
New Material Technology（Mineral castings）----This is a product we manufacture.The size is similar.
https://grabcad.com/library/new-mate...ral-castings-1

[ardenum2]

That's what I thought.
A large part of the reason why mineral castings can finally be accepted by customers is cost.
So in 2013 I started thinking about how to control costs.Thankfully, I've learned how to control costs in many ways, so price isn't an issue for me.
First molds, from the earliest steel, to the present wood (wood and steel mixed).
Own stone factory and get qualified stones.And so on, a lot of work has been done.
I also made a very bold attempt to build a gantry machining center milling machine. 6m*3m*0.8m,
If you have a good product, we can discuss it together.
New Material Technology?Mineral castings?----This is a product we manufacture.The size is similar.
https://grabcad.com/library/new-mate...ral-castings-1

I'm gonna send you 3 mineral casting parts for a quote soon. Before I do I have a few questions.

Do you make parts with just threaded inserts and not a long steel bar? (picture 2)

If you do, have you got standard inserts that you make in house? (picture 1)

[Mr-MaW]

I'm gonna send you 3 mineral casting parts for a quote soon. Before I do I have a few questions.

Do you make parts with just threaded inserts and not a long steel bar? (picture 2)

If you do, have you got standard inserts that you make in house? (picture 1)

Photos of such products we have, this needs to use steel molds, so the cost is very high. In order to save mold costs, I now use embedded guides.
The position accuracy required by the entire steel plate is not high, and you can post-process the accuracy you want. And the force of the overall steel plate, the rigidity of the equipment will be better.
Of course, if you don't have high requirements for cost and delivery, I can use the kind of product with photos. Steel molds, high prices.

https://grabcad.com/h.w.ma-1

My English is not good, hope you understand what I mean.
Tell me your email address and I can send you a photo to deepen your understanding.

[ardenum2]

Since I decided to use linear motors instead of ballscrews, it got me overly excited and I decided to take a swing at cast iron. Found over a dozen foundries in china with very good prices for both casting and machining, but overall shipping prices for a +500kg shipping is nasty, nevertheless here are two structures I came up with. Both offer almost the same configuration capabilities. You can mount anything you want to the front for ultimate flexibility.

Actual size comparison.

[awerby]

I've read that companies that made precision machines out of cast iron would typically leave the castings outside for a couple of years to "season" before machining the surfaces. Apparently it takes that long in the weather to work out any residual stresses in the material and improve its machinability. I've heard of heat, cryogenic and vibratory treatments that allow that time span to be compressed, but I doubt the Chinese foundry you found is doing any of that, although you might ask them about it. Here's some reference material to consider: https://www.totalmateria.com/page.as...ite=kts&NM=124

[peteeng]

Hi Ard - since your getting quotes try Whites in Oz.. may surprise you. Peter

https://whiteindustries.com.au/

[joeavaerage]

Hi,

I've read that companies that made precision machines out of cast iron would typically leave the castings outside for a couple of years to "season" before machining the surfaces

That is true. Remember also that many of those same companies are making castings on a production scale that allows them to sit for that length of time whereas you and I do not.

The standout property of cast iron is its dimensional stability, even straight from the mold. With heat treatment, either thermal or vibratory, its ready to rock. Sure aging is nice but not really required.
Cast iron has the same dimensional stability as stress relieved steel.

I had my axis beds cast and they are perfect, the only dimensional change they suffer is thermal expansion or contraction or as they rust away over the next 100 years, were I to let them rust.

Casting in iron is a tried and trued means of making machine parts, the only thing that prevents its adoption by hobbyists it cost. As Ardenum has discovered actual cost may not be as bad as you might imagine,
certainly not cheap, but possibly not prohibitively expensive either.

Craig

[joeavaerage]

Hi Adenum,
I note that you have used hollow structures, and they require sand cores and adds to the cost hugely.

I would suggest that you consider very carefully the design with a view to eliminate multi piece patterns and especially sand cores. Ideally you'd have a single pattern that requires a drag and cope
and no more. That minimizes the pattern making and molding costs. Thereafter casting is still not cheap but not outrageous.

You may recall in another thread I recently priced a simple part, ie just one pattern required, and a casting weight of 50kg for $900NZD ($550USD). Not cheap...but not prohibitively so.

Craig

[ardenum2]

I've read that companies that made precision machines out of cast iron would typically leave the castings outside for a couple of years to "season" before machining the surfaces...but I doubt the Chinese foundry you found is doing any of that,

I've read the same. I think most of the foundries said they stress relief in an oven and machine when its cooled off. thanks for that webpage, a lot of good knowledge in there.

Hi Adenum,
I note that you have used hollow structures, and they require sand cores and adds to the cost hugely.

It's for lost foam, go big or go home! jokes aside, the wall thickness is 15mm to keep the weight in check. A draft angle on that thickness would destroy the wall at the ends.

Hi Ard - since your getting quotes try Whites in Oz.. may surprise you.

added them to the list.

[ardenum2]

What happens in the end is a matter of price. I'm covering all angles for the best option available:

cast iron in china + stress relief + machining + shipping

vs

cast iron locally using my lost foam patterns + stress relief + machining + shipping

vs

mineral cast in china + machining + shipping

vs

mineral cast by me + machining at a local company + shipping

[joeavaerage]

Hi,
the company I approached just recently does, in fact, specialises in lost foam. But the owner of the company told me that for large parts lost foam is not the right technique,
aside from cost. The mold is ceramic and its fragile and with larger parts it fractures as the metal cools. For larger parts greensand molding is still preferred and is much cheaper.

The draft required is about 1 to 2 degrees, and is to allow the pattern to be withdrawn from a greensand mold......draft is not required for pouring or any other purpose.

Craig

[peteeng]

Hi Ard - Have you seem linmot motors? Peter

LinMot & MagSpring - Linear motors and linear motor systems

[ardenum2]

Hi Ard - Have you seem linmot motors? Peter

LinMot & MagSpring - Linear motors and linear motor systems

tubular linear motors, I've seen them, not this brand specifically, but I had a look at their design through papers and through a company called anca, their linX series motors. https://motion.anca.com/Products/Mot...C2%AE-S-Series

tubular design is actually very good, it has the best of both worlds between ironcore and ironless. It eliminates cogging like ironless but its an enclosed construction so the flux doesn't spill outside the motor like in ironless, which usually has bad EMI issues. This also lets it retain a high thrust comparable to ironcore. Looks like it would also be much easier to refit into an existing system instead of a ballscrew.

Unfortunately linx are insanely expensive. Even LinMot that you mentioned, I see just the motors going for $900-$2000 on ebay.

[peteeng]

ANCA another good Oz company... Peter