Yet another question about self-design

So, here I am, sitting on a bench at the company I do my Architecture/Furniture design internship.

After giving this a lot of thought, it has been decided. My Reprap Air 2 will be turned into a Tantillus.

The design will be done by me, but I would like to incorporate parts of other designs aswell. The Tantillus looks like a great machine because the mass of the print bed is taken out of the equation for printing speed. This will also mean: less vibration, less chance of a part coming off and better control over temperature since there will be a frame enveloping the machine completely.

Question no. 1 is about size.
I see a lot of tantillus' that have small print surfaces, why is this?

Is it because the smooth rods will hang when they get too long? Is the printer less accurate if the X and Y sizes are increased?

My goal would be to get a 200x200x150 printing area. I never printed higher and height is not important for me. If something is tall I usually cut it in half and glue it after printing.

The frame will be made out of aluminum extrusions, because I like how it looks. However, it can be smaller than the usual 20x20 extrusions used for a Mendelmax 1.5 but it might also be constructed of 4 to 6mm acrylic plates or very thin aluminum plating 2 or 3 mm thick. As the surface and corners will provide rigidity.

Is there an official model for the Tantillus or a shop that sells premade frame kits that I can take a look at? I found one shop on tantillus.org but their shop is closed.

After thinking a lot what to do, I now realise that it's no use to design a new Air2 frame for my old air or to try and improve the MendelMax. No, the whole Tantillus setup of X,Y and Z is so incredibly rich in advantages that this will be the best idea.

Hope to join here soon with my own Tantillus!
- Marinus

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Ohmarinus
Question no. 1 is about size.
I see a lot of tantillus' that have small print surfaces, why is this?

I originally designed it to be a portable machine after traveling with my Prusa, hence the smaller size.

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Is it because the smooth rods will hang when they get too long? Is the printer less accurate if the X and Y sizes are increased?

Not entirely sure if it changes the accuracy. I can tell you there are a few 200mm wide machines out there (Kburr's and [www.youtube.com] ) to name a few. For going deeper you need to consider a printed cantilever is not very strong. If you want a larger Tantillus variant I would have a read through the Ingentis thread where we discussed the pro's and con's of building a larger machine and the solutions we cam up with (i.e. lifting the bed from the sides instead of one edge and larger diameter rods to overcome the effects of having more cable wrapped on the rod).

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My goal would be to get a 200x200x150 printing area. I never printed higher and height is not important for me. If something is tall I usually cut it in half and glue it after printing.

I always recommend building a wider/taller machine and keeping the depth the same. This is because printing taller does not increase the warping where as printing wider/deeper does.

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The frame will be made out of aluminum extrusions, because I like how it looks. However, it can be smaller than the usual 20x20 extrusions used for a Mendelmax 1.5 but it might also be constructed of 4 to 6mm acrylic plates or very thin aluminum plating 2 or 3 mm thick. As the surface and corners will provide rigidity.

Have you looked at Goopyplastics t-slot Tantillus or Ingentis? Ingentis is a proven design and has a build area greater than 200x200x200 and is also t-slot.

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Is there an official model for the Tantillus or a shop that sells premade frame kits that I can take a look at? I found one shop on tantillus.org but their shop is closed.

Yeah I closed the shop do to lack of time after becoming a stay at home dad. I do have 1or2 2nd Tantillus acrylic frames left if you are interested but I do not have a laser cutter and can not make larger or new ones. SeeMeCNC used to sell wooden kits and a company called Wardtech also sells parts but they are not always of the best quality.

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After thinking a lot what to do, I now realise that it's no use to design a new Air2 frame for my old air or to try and improve the MendelMax. No, the whole Tantillus setup of X,Y and Z is so incredibly rich in advantages that this will be the best idea.

Hope to join here soon with my own Tantillus!
- Marinus

I am still here to help out and improve things as I can but the machine with the most active development is Ingentis which is directly based off of Tantillus and would be a good starting point for what you want.

Edited 2 time(s). Last edit at 05/21/2014 03:31PM by Sublime.

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200mm wide would certainly be handy. I have done so many designs where I run out of room on one axis only. I think rectangular is a great way to go.

If anyone wants laser cut bits in New Zealand I am happy to hellp as I have my laser up and running now.

Cheers
Keith

EDIT: Adding my URL

edns.co.nz

Edited 1 time(s). Last edit at 05/22/2014 01:06AM by Robonz.

Hey guys thanks for the wonderful replies.

I have been looking into the machines, and I don't think the goopyplastics version is what I am looking for.

By searching through different models I have found out it is probably best to use these fishing-wires to move the X- and Y-axis. Also, the goopyplastics variant doesn't have a 200x200x200 build envelope, the machine seems to have a footprint of 200x200, probably not something that is going to work when it's upscaled.

If we upscale the machine, hypothetically, the 6mm and 8mm smooth rods might not be strong enough to stay straight, so I will probably have to upscale that too, to 8mm and 10mm smooth rods. However, it is easier for me to come by purely 8mm bronze bushings, so maybe I'll just make everything out of 8mm rods. Also all the bearings are easier for me to source that way. I expect the 6mm smooth rod choice was made so the X-movement would not be too heavy?

Today I received my new PLA roll of filament, it is a nice green color, and will be used to print the structural parts of the printer.

After printing the structural parts I will switch to my other printer to print the remaining parts, that will probably be done in ABS, but I'm not sure yet. I secretly want to switch to printing PLA with both printers. This makes it cheaper for me to buy printer plastics and easier for me to switch out different filament types.

Also, in the end, maybe I will put a dual extruder in the Tantillus, so I expect that I need a little bit of extra X-axis space in the frame.

I've read that using a ballscrew rod is not such a good idea for the Z-axis, however, I had already sent an order to a webshop, I tried to cancel it but am not sure if they read it in time. Is using a ballscrew really that bad? Oh, btw, it's a stepper motor that has the screw already connected to it.

None of the machines use any 6mm rod that I know of. It does use 5/16" rods on the outside because precision 8mm rod does not fit in 8mm id bearings. But 5/16" is 7.92mm and the 0.08mm allows the rods to fit into the bearings with ease. You can can turn down the ends of 8mm rods to fit and may even be able to simply sand them down with the rod in a drill and holding sand paper.

There is nothing wrong with a ball screw, it just costs a lot and does not necessarily remove Z wobble.

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Hmm, I am sure that my 8mm ID bearings fit right over my hardchromed 8mm rods Maybe the European standards are different. I know that the milling tolerances are a bit different over here, at least, thats what the company told me that sell these materials. They are very experienced in this field of work.

They even fit more exact than any other kind of exact fit I've ever had. I never ever tried this, but now after I read your reply, I put it on the rod and wow, it feels weird to say, but it feels nice to feel how exactly they fit together hahaha.

By the way, are you the guy in the hoodie being interviewed about the Tantillus by an older man over skype or something on youtube? I think I saw your interview, it was nice to see what you had to say


I have been looking for cheap extrusions in my area, and have found a few, however, I think that the openbeam/misumi extrusions are the best when they are already cut for you. I tried cutting a few myself, but they all have badly jagged edges.

There is one supplier in the Netherlands that can deliver some extrusions to me for a good price, but the cutting cost is very high, does anyone know if the openbeam company charges a lot for shipping overseas?

Edited 1 time(s). Last edit at 05/24/2014 02:50PM by Ohmarinus.

You are correct that some 8mm rod does fit in 608 bearings but in that case the LM8UU's may be a little loose on the same rod. The rods I use are rated at +/- 13 micron but always came in at +/- 5 micron which was too tight of a fit for the 608 bearings, but perfect for the LM8UU bearings.

Yes that is me in the video.

For the cutting of the t-slot you can buy the t-slot from one company and then find a machine shop in your area with a "cold saw" to cut them for you.

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Ha, nevermind, there is a Makerbeam headquarters in my country. They are not expensive. I think this is the best solution.

[www.makerbeam.eu]

I'll get started on my design right away! I will keep in mind the available sizes of these beams already. The hardchromed rods are easier for me to order in custom sizes than the makerbeams.

Is there a place where I can see a 3D-model of a tantillus where it is already assembled? So far I have only been able to find stl's of the different parts needed for printing. I would like to rotate, zoom and look around inside a put-together 3D-model to 'really' understand all the workings

I cut my extrusions with a proxxon cutoff saw, but you can use any cutoff saw, you want a carbide tipped blade with as many teeth as you can get.
I cut the chromed rods with the same saw using a carbon fiber cutoff wheel, you probably can't do that on a larger saw because of the lower RPM's.,, I have on the past marked the rods and used An angle grinder to cut them, my band saw will not cut through the hardened exterior.
Drill rod you can cut relatively easily.

If you are going much bigger than the standard 100x100 print area, you really want to move up to 20mm extrusions, openbeam has very little tortional stiffness and my larger design would visibly flex when picked up by opposite corners.

Edited 1 time(s). Last edit at 05/24/2014 04:32PM by Polygonhell.

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My blog [3dprinterhell.blogspot.com]

For a complete view you can open the blend file in Blender. If you have solid works you can use WillWorkForPlastic's metric assembly.

I just added assembly stl's to the github repo. There are two, one with the laser cut case and one just the insides.

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Since the server is not letting through my message, I made a screenshot haha.



Edited 1 time(s). Last edit at 05/25/2014 05:02AM by Ohmarinus.

The carriage does use two bearings side by side but one is a short LM8SUU otherwise the carriage is too big to get 100mm build area in the original size case. For a larger machine you can use a long one in its place and even make the carriage wider/deeper.

Don't let the pictures lead you to thinking it is any easy machine to assemble. The printed machine is the hardest to assemble and then the laser cut case makes it easier and the t-slot even easier. But no matter what it has very little clearance between moving parts and requires careful assembly to make sure everything moves smoothly.

I also just updated the assembly stls to not have the floor in them that I used for rendering the images.

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I think Polygonhell's design is very nice, I'm also thinking of Direct Drive, so I have placed an order for couplers that go from 5mm ID to 8mm ID. They are flexible stainless steel couplers with set screws.

Also currently in the process of ordering OpenBeam, I have contact with the Dutch manufacturers now about what extrusions to use. Apparently it is impossible for them to order custom lengths, so I would have to adapt my design to sizes that are already available.

One more thing about the LM8UU bearings, I've tried to wiggle them on my MendelMax that has been functioning for 6 months now and the bearings show ZERO signs of being less tight. I really think this is due to the tolerances that are different in my country. The bearing manufacturer has written me something about this, but I can't find it back, it was a whole year ago when I had ordered the parts for my MendelMax.

Also, I read something about the fishing thread sometimes causing the system to go out of calibration. Can it slip or something? And is it an idea to make the diameter of the smooth rods effectively bigger by adding a guide wheel on the smooth rods? I can imagine this guide wheel can by itself then slip a bit, so maybe the fishing thread on the smooth rod all by itself is enough.

How do you clean the smooth rod from any lubricants? When I order it from the factory, there is a thin layer of protective lube on it.

I've decided that even with the bigger size, it will be possible to get a square and rigid frame with just 15x15 OpenBeam. I'll first try with printed parts, if I don't succeed, I will design and order a custom set of lasercut plates to square out the machine. Especially a square with a large square hole in the middle for the top and a square plate for the bottom part of the machine (which will not be lasercut, but just cut into square and with a digital CNC mill the holes will be added in exactly the right places).

The only times I know of the cables being an issue is when the tensioning loop is on the wrong side of the bolt and washer that are supposed to hold them in place. Beyond that not having the cables tight enough and not having the axis squared can cause binding.

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Ah, I'm sorry, what do you mean with tensioning loop?

In step 8 of this section [www.tantillus.org] you tie a loop in one of the cables and then later you thread the other end of the cable through this loop and use it as a block and tackle to tighten the cables. But some people have pulled the loop through the x/y end and then tightened the bolt which results in bolt only holding one side of the cable.

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As Sublime said the strings work and work without any issues if built properly. What I don't like about the stings is the time it takes to pull them on and off the machine if you want to do some maintainance. e.g if you needed to remove a shaft or bearing and put it back. But I do believe you get better performance with strings than belts because they are less stretchy than a belt.

To answer your question earlier. When I get new shafts I clean them down with isopropyl and a rag. I also chamfer the ends and most importantly straighten them. .When the machine is fully assembled I then lubricate the shafts. I also found that some skate bearings fit much better than others so its good to have a few "different" sets on hand.

Cheers
Keith

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Robonz
As Sublime said the strings work and work without any issues if built properly. What I don't like about the stings is the time it takes to pull them on and off the machine if you want to do some maintainance. e.g if you needed to remove a shaft or bearing and put it back. But I do believe you get better performance with strings than belts because they are less stretchy than a belt.

To answer your question earlier. When I get new shafts I clean them down with isopropyl and a rag. I also chamfer the ends and most importantly straighten them. .When the machine is fully assembled I then lubricate the shafts. I also found that some skate bearings fit much better than others so its good to have a few "different" sets on hand.

Cheers
Keith

Thats a nice explanation, however I don't have access to such a workshop atm and in my country there are not so many workshops that are equipped well. Most blacksmiths/metalworkers in my town only do stuff like welding fences. Which is kind of depressing to see.

I will avoid chinese smooth rods (even though they are quite cheap). I wanted to order them from Robotdigg, but I will refrain from that. So I will only order the fishing wire, bronze bushings and other related things over there.

Maybe even add a stepper motor with a leadscrew. I tried to order one in my own country, but it turned out to be too expensive (~$340/170 euros) for one leadscrew attached to a stepper motor).

I hope the tolerances on those sintered bronze bushings are tight enough!!!! Otherwise I'll have to do with LM8UU again, but I have some experiences with the oils in those bearings going onto the rod and I'm afraid it will contaminate my smooth rods on the spot where the wires go on. Maybe it's a nice idea to design a seal that can be mounted on the smooth rod next to where the wires are placed.

Sublime, I completely missed your assembly guide! I'm so sorry, it has all become much more clear to me now!!

Edited 1 time(s). Last edit at 05/27/2014 07:54AM by Ohmarinus.