CRP4896 Standard to Linear Rail Conversion

[nlancaster]

here is what I was cutting today and the basic setup I used.

Don't be deceived by the finish on the side, it is smooth to the touch. And the cut edges are razor sharp, just need to deburr all of them.

[wmgeorge]

I don't know if you have a Goodwill store or the like, or even new it would be cheaper than $300. Buy an aluminum cookie sheet (with lips) and screw down at the edges with sheet metal screws and silicone sealer. Place your work piece inside that and go for it. When done either toss toss the sheet or save, you decide. Not perfect but Fast and cheap.

The MDF could be easily sealed.

[wmgeorge]

So in preparation for cutting the aluminum for the upgrade, I finally got around to building a mist coolant system.

I don't have a picture of the nozzle installed on the machine, but here is a link to amazon for the one i used.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Attachment 423712

Thanks for posting, I was looking for something like this.

[nlancaster]

wmgeorge the cookie sheet is a good idea!

[GME]

Thank you for sharing. Given the sizes of the pieces you milled vs the size of the MDF, I'm surprised to see the moisture contained so well. On my mill, wet chips seem to go everywhere. But then, what I cut on my mill is elevated above the table in a vise. I'm sure the elevation ensures chips get thrown farther.

Nothing deceiving about the edge. It looks smooth to me. No obvious chatter.

I recognize the lower plate. It's the plate that mounts on the X axis linear rails to which the Z axis mounts. The upper plate looks like the horizontal one that mounts to the lower plate in your photo and is the one the stepper driver mounts on.

Just curious, but what linear rails are you using? I used Hiwin 25mm (Avid uses 20mm) for the Y axis and Hiwin 20mm for the X. The Hiwin bearing blocks for the 20mm rails have the same mounting hole spacing as the ones Avid uses. I used a medium preload vs Avid's light preload, which I'm very happy with. Medium is hard to find in the Hiwin copies, but are readily available in Hiwin. If you haven't purchased your linear rails yet, you might take a look at this company. https://motionconstrained.com/ The prices are as good as I've found for Hiwin, and the service is great. The parts arrived in perfect condition.

I'm thinking HDPE or UHMW might be a reasonable substitute for MDF, being waterproof and all. However, given the cost, zeroing the cutter to the surface of the HDPE would be essential. Seeing your setup stimulated some ideas.

Thank you again.

Gary

[nlancaster]

So I do not notice the chips that get sent flying having a noticable amount of liquid on them. The coolant seems to stay confined to the surface of the part, I only had so much water flow off because I was having some issues with air bubbles and had to crank up the coolant to get flow.

The coolant only seems to effect a small area near the surface of the cut MDF, it does not "soak" into the entire MDF.

If I was going to be doing a huge amount of machining of the same part I would totally go for a UHMW or HDPE fixture plat with troughs to catch any coolant.

I would love to find a cheap source of plastic sheet.

I have not yet purchased my rails, I have been considering the automationoverstock BLH rails, Kent at automationoverstock/automation4less says they are very good.

wmgeorge, you are welcome on the picture of the mist coolant system. It works well, in 3 hours of cutting with way to much fluid flow I managed to drain about 1/2 of the coolant compared to the picture I posted here.

[nlancaster]

Prices of what I need.

[GME]

I would love to find a cheap source of plastic sheet.

Me too. The cost of the stuff is almost obscene. Ditto for aluminum plate and cast aluminum.

Prices of what I need.

If they are as good as Hiwin, it's a great buy. I'm impressed by the fact you can get medium preload. As far as I can tell, pretty rare in Chinese built linear motion carriages. I hope the BLH works out for you.

Gary

[nlancaster]

Gary, I am going to give them a try, gamble the $880.....

I bought my .750 6061 thru my work, so got about a 25% savings over retail.

[GME]

I'm green with envy. I'm retired now, but never worked anyplace where I could buy metal or plastics through work. I used to be able to buy lots of the good stuff from Boeing Surplus brick & mortar store in the Seattle, WA area. Steel was $.25/pound. Aluminum was around $1/pound. I don't recall about plastics, but the price was similar. Essentially, I was able to buy for scrap price. That was years ago. I spent many Saturdays there. It was an adult's toy store.

Boeing closed the store and now has an online presence. Rather than having thousands (sometimes 10s of thousands) of items for sale at any given time, the online store, which operates as an auction, only has a few things at a time, and frequently in larger lots. There are still deals to be had, but you have to keep on top of it. Also, you have to live in the area, unless it's worth coming to the Seattle area to pick up. They don't ship.

Gary

[nlancaster]

I once got the chance to go to the Boeing Surplus store in Kent, it was fantastic..... so sad when it closed.

I live down in the Portland area.

[ger21]

Gary, I am going to give them a try, gamble the $880.....

Be prepared for a $200 shipping charge.
Shipping on my 3000mm rails was $170 a few years ago.

[nlancaster]

Well I would be paying that $200 weather I was getting Hiwin or BLH.

[GME]

Well I would be paying that $200 weather I was getting Hiwin or BLH.

Not necessarily. I bought my Hiwin from Motion Constrained. Motion Constrained has free shipping! See my earlier post for the link.

Gary

[nlancaster]

Gary, I looked at Motion Constrained, they are more then $200 higher then Automation4less for Hiwin.

But as I said, i am going to take a gamble on the BLH rail from automationoverstock, kent swears they are good and several US equipment manufacturers are using them. He for obvious reasons will not share the name of those OEMs.

[GME]

Gary, I looked at Motion Constrained, they are more then $200 higher then Automation4less for Hiwin.

But as I said, i am going to take a gamble on the BLH rail from automationoverstock, kent swears they are good and several US equipment manufacturers are using them. He for obvious reasons will not share the name of those OEMs.

How odd. When I bought my stuff, I compared Automation4Less to Motion Constrained. Motion Constrained was hugely cheaper.

I just did a price comparison on my HG 25mm for my Y axis.

Automation4Less

Rails (1660mm)= $297.97 X 2 = $595.94
Bearing Blocks= 4 X $67.64 = $270.56

Total = $866.50

Same from Motion Constrained = $526.22

I stopped there. Just my Y axis was $340 cheaper.


Don't get me wrong. I'm not pushing one brand over another. I'm sure the BLH will work fine. Avid uses generic Chinese rails and has plenty of happy customers. The odds are good that yours will be at least as good as the ones Avid uses, and may even be better.

Gary

[nlancaster]

Gary, I must have been looking in the wrong place. I would also have to cut rail. Let me look again.

Found it, i was in the complete linear guide section, not the rail and blocks section.

But still not as cheap as the BLH rail.

[nlancaster]

Commited now, ordered the BLH rail. Only $52.80 in shipping cost.

[GME]

Do you plan to use the Avid technique for aligning your new rails, or do you have an alternate plan in mind? I'm anxious to see how it goes. Linear rails have a reputation for being difficult to install on extrusion-based machines. Avid's technique (with the positioning jig) is okay, I suppose, but its success is dependent upon the rails being 100% straight and everything being coplanar. There is no straightness tolerance for rails that I have ever found, so relying on a jig alone may not produce a perfect result. Did you use a machinist level when you constructed your machine to ensure all was level and coplanar? If not, I'm thinking you could have issues. Also, because your Y axis rails are mounted on the sides (versus mine on top} you may have an interesting adventure getting them installed to a fairly exacting tolerance. I'm sure there are a number of folks who will be interested in seeing how you manage it all - myself included.

Good price on shipping. Free is better, but $52.80 is pretty darned good, especially given the length of your Y axis rails. As I understand it, when when the parcel size gets over 108" in length, the shipping cost goes up - at least for UPS shipments. Sounds like you got a good deal all around.

Gary

[nlancaster]

I did not use a machinist level to level the machine.

As far as I can tell the tops of my rail are as flat as I can possibly make them.

I was going to use a modified version of AvidCNCs install method, but not just from the ends. I was also going to hit a few places in the middle with the clamping fixture before tightening the rest of the screws.