Maker Slide Runout

Does anyone have any experience with these slides? How much runout or bow do they have per foot? I know regular extrusion has up to 0.025 -in runout. 0.635mm. It's been asked in several forums but noone ever got a straight answer.

I don't think you will ever get a straight answer. Extrusion is not a particularly accurate process and the numbers, when given, are normally awful. In my experience I've never seen a piece of extrusion with nearly as much bend or twist as allowed in the datasheet.

I would generally be more worried about extrusion bending due to gravity/loading. The stuff isn't particularly rigid, especially since the outer profile has so many gaps for tslot nuts. I have put an 8" piece of makerslide on a surface plate and could not get a feeler gauge under it. Either it was flat, or it sagged enough to conform to the flat surface.

Note that by using makerslide you are already stuck with fairly poor quality linear motion (plastic v-wheels on shoulder bolts?). If precision matters for your project, extrusion straightness will just be a drop in the ocean.

Edited 4 time(s). Last edit at 03/04/2015 04:02PM by 691175002.

691175002 you're rightn that 20 module extrusions can bend under load, even if it won't conform as easily as you think. Hopefuly we don't load them with a pound or two V-wheel guides are much better than you thing through. You should give them a try someday. Derlin wheels are strong, low friction and more durable than rubbish LM/SBR series bearings. In some configuration they allow more load in every direction than tiny MGN rails that bends even faster.

Embed, there's a way to know the moment of inertia of a makerslide rail. Some softwares like solidworks can calculate any profile. Just find the opensource plans, reproduce the profile and run a stress test. But I don't think it's necessary. Base your calculations on the standard 20x40 Mitsumi rail. You'll be able to find any data about it. Then you'll know the Makerslide do a bit better on the 40mm side because of the two v-lips, but not that much. That will make the tolerance for your calculation on that dimension. On the 20mm side, it's strictly the same. You don't need more precision on your calculations. Note, if the profile is below your needs, it's possible to greatly increase the profile stiffness buy compressing the profile on its lenght with a screw passing all through the center hole between two plates on the ends. Nobody thinks about this old bridgemaker technique. It just works.

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Collective intelligence emerges when a group of people work together effectively. Prusa i3 Folger (A lot of the parts are wrong, boring !)

I have got an OrdBot that is made with Makerslide. There is a forum for Makerslide builders, laser engravers, not just the OrdBot:

[www.buildlog.net]

I know that a number of companies around the world make the Makerslide profile and I have heard of quality problems in the past with some of them. I am in the UK and I ordered my kit from ATI in the States.

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Zavashier
691175002 you're rightn that 20 module extrusions can bend under load, even if it won't conform as easily as you think. Hopefuly we don't load them with a pound or two V-wheel guides are much better than you thing through. You should give them a try someday. Derlin wheels are strong, low friction and more durable than rubbish LM/SBR series bearings. In some configuration they allow more load in every direction than tiny MGN rails that bends even faster.

I guess my point is that if you are concerned about the accuracy of an extrusion based design your first question should be "will it bend?", not "is it straight?". I'm very confident that deflection will be a much larger contributor to overall error than any bend or twist in the extrusion. Even more so if you add deflection from the v-wheels and their mounting plate and throw some acceleration into the mix.

Edited 1 time(s). Last edit at 03/04/2015 05:53PM by 691175002.

Ok, thanks for the replies. After seeing this and looking more on the net , think I'll stay away from maker slide right now. I'm probably going to have to come up with some other solution because there are no linear bearing or slide rail dealers in the states except for professional. And I just don't do ebay, china. ali anything. Learned my lesson the hard way on those.

I have an ord bot and a Shapeoko. I've had zero issues with either one from the makerslide rails.

@Embed, try Openbuilds.com, it's another opensource V-wheel profile. Less expensive, with 20x20 ; 20x40 ; 20x60 and 20x80mm profiles. Better IMHO because you can run your wheels on any groove of the profile. They provide mini wheels and hardened steel ones, and a open rail, like Hepco V-rail, a standalone rail that can be mounted on any flat part. It's in the USA.

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691175002
I guess my point is that if you are concerned about the accuracy of an extrusion based design your first question should be "will it bend?", not "is it straight?". I'm very confident that deflection will be a much larger contributor to overall error than any bend or twist in the extrusion. Even more so if you add deflection from the v-wheels and their mounting plate and throw some acceleration into the mix.

Well, you totaly dislike that technology. You can make other choices for your machines if you like. All depends of the admissible load of a system. I use V-groove guides for a while, and it's an inexpensive, acurate and durable system. I used them to carry some aeronautic parts over 10.000 pounds on curved rails. Not with Makerslide rails and wheels of course, with Hepco adapted ones. I don't ask myself questions. I calculate which system fits better for the load. Then I'm confident. The derlin wheels are precise enough and can hold much load than the profile will stand before bending too much. A gantry made of a signle 20x40x400mm profile with plates, hotends, fans, thansmission and wiring will be far to weigh a pound. So the profile will be stiff enough. The plates are 5mm aluminium, they will not bend or twist as easily as common printed plastic parts. For most of 3D printing applications Makerslide/Openbuilds systems will be just fine. Don't trust me, calculate by yourself.

Edited 2 time(s). Last edit at 03/05/2015 08:16AM by Zavashier.

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Collective intelligence emerges when a group of people work together effectively. Prusa i3 Folger (A lot of the parts are wrong, boring !)