Mendelmax 1.5 vs 2.0

Hey,

I assume that people have by now noticed MendelMax's announcement for 2.0 [www.mendelmax.com]

I was hoping to see what people think regarding the new design, and the feasibility of printing one versus building it as a rep-strap, the announcement mostly mentions ease of assembly and manufacturing benefits so I am assuming that there is no resolution/quality change versus the 1.5.

Me and a friend had started planning to make 2 MendelMax 1.5 to add to my current collection of a Sells mendel and a Rostock.

For now it seems to me like MendelMax 1.5 is more suitable to being a true 3d printable reprap than the 2.0

From reading through the site, it seems that the 2.0 version will be just as printable as the 1.5 version, being that all the flat plates are small and printable, with the exception of the front and back plates, which could be replaced with extrusions. It looks to be a nice printer.

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First impression, less RP, more metal work. A further move away from the Reprap idea. It's ok saying anyone can build it in a workshop, but I don't even have a kitchen table!

Perhaps the design will grow on me, but it seems to lack the elegance of previous "triangle" designs, it has more of a utility look. But if it works well.... clearly the goal was to design for volume manufacture. Not much mention about cost - will it be cheaper than MendelMax 1.5?

Edit: I am Maxbots, the Designer of the MendelMax

The goal of the MendelMax 2.0 is to be fully printable, but to require no printing (or at least as little as possible). I guess it depends on what you consider the "RepRap idea". If you define that the traditional way, as "A printable 3d printer", then you are incorrect, the MendelMax 2.0 remains just as printable as past MendelMaxes.

If on the other hand you define "the RepRap idea" as "a 3d printer that anyone can build at home with no special tools and with reasonably accessible components", than the MendelMax 2.0 is arguably the most accessible RepRap yet. You can build a 100% functional MendelMax 2.0 that will perform just as well as a machined one with nothing but a hand saw and a drill.

Now in the traditional RepRap lingo that would be a RepStrap, but I find the distinction tends to be dismissive and unfair. A printer should be judged on it's technical merit, not on it's printed content. If it prints as well as a "true" RapRap, it is fully printable (even if the exact unit is not itself printed), and it performs as well as other RepRaps, why dismiss it as "just" a RepStrap?

As for the look, I suspect if you saw it in person you would disagree. I think it is far better looking than the previous MendelMax. The fact that it is completely open in the front emphasizes the print, not the printer. Aesthetics are a personal matter, so what appeals to one may not appeal to another, but I suspect you will change your mind once you see more pictures of the new design..

Edited 1 time(s). Last edit at 12/27/2012 08:35PM by kludgineer.

The main benefits compared to the MM1.5 are a slightly larger build area (especially in Z), much easier assembly, and a more visually open design. "Resolution" of any RepRap is determined entirely by the pulleys and lead screws you use.

Since pulleys and lead screws will vary depending on who buys and builds the printer, I can only speak to the capabilities of the kits that we will be selling at Maker's Tool Works. We use 20 tooth GT2 pulleys, which deliver an XY resolution of 1/80th MM. To the best of my knowledge, there are no currently available kits with a higher resolution. On the Z it uses 2mm pitch lead screws which give a Z resolution of 1/1600 mm. Depending on the nozzle diameter you choose and how long you are willing to wait for prints to complete, it is capable of layer heights from .05mm or less up to .4mm or more.

>We use 20 tooth
> GT2 pulleys, which deliver an XY resolution of
> 1/80th MM. To the best of my knowledge, there are
> no currently available kits with a higher
> resolution.

I don't understand how you can work that out by just talking about the pulleys. Don't you also need to talk about the stepper resolution and the sub-stepping to arrive at a value?

it is academic anyway because belt stretch, machine rigidity and extrusion inconsistencies will swamp the errors from the theoretical resolution.

I love the ideas that went into MendelMax 2.0

I dig the idea of parts that can be printed or cut from sheets (depending on what is available to you). I bet laser cut plywood would work with this build...

This reminds me that I want to attempt the 3D print the Laser Cut version of the Printrbot I know a few folks were trying.

True, but almost everyone runs at 1/16 step mode with 200 step/rev motors, so I was basing my numbers on those values. It is possible to increase the resolution by using 400 step/rev motors or by using drivers that support 1/32 step mode, but that will trade max speed for resolution. Of course using a lower step mode or motors with fewer steps will decrease these values, but almost no one does anymore, certainly no one selling a modern kit.

In practice, as Greg Frost noted, you reach a point of diminishing returns. When your nozzle is .25mmm diameter or larger, the benefit of a resolution higher than .0125mm becomes rather academic (as well as the various other factors he mentions). Because of these factors, I don't see trading travel speeds for basically unusable resolution as a worthwhile sacrifice even if you do not consider print speed to be that important..

Idolcrasher Wrote:
-------------------------------------------------------
> I love the ideas that went into MendelMax 2.0
>
> I dig the idea of parts that can be printed or cut
> from sheets (depending on what is available to
> you). I bet laser cut plywood would work with
> this build...
>
> This reminds me that I want to attempt the 3D
> print the Laser Cut version of the Printrbot I
> know a few folks were trying.

Thanks Idolcrasher. I put a lot of thought into the design, and I am quite proud of how it came out. I hope it really opens things up for a lot of people.

Most of the parts could definitely be cut from plywood, though you would sacrifice some rigidity. I would say the same parts that won't be printable as-is would also not be usable in plywood, mainly the X ends and Y carriage. For those parts either cut them from metal by hand or use the printable replacement parts that are forthcoming.

kludgineer Wrote:
-------------------------------------------------------
> Now in the traditional RepRap lingo that would be
> a RepStrap, but I find the distinction tends to be
> dismissive and unfair. A printer should be judged
> on it's technical merit, not on it's printed
> content. If it prints as well as a "true" RapRap,
> it is fully printable (even if the exact unit is
> not itself printed), and it performs as well as
> other RepRaps, why dismiss it as "just" a
> RepStrap?

Right, so you admit it is a RepStrap. I wasn't dismissing it because of that. But you seem to be rather sensitive about exactly how it is defined. I really don't think you are being honest with yourself. It is funny how the marketing speak comes in the door at the same time as commercial opportunity.

And still, you mention all its benefits, but not cost. It sounds like you have designed it to reduce your manufacturing costs, but will offer at same retail price based on improved performance. This improves your profit margin, but does not pass on cost saving to the customer.

I don't have a problem with commercialising and moving away from Reprap, good luck to you. But I think it helps all round if we are honest about what is going on.

That all aside, the interesting aspect is that several of the recent printer designs are converging on the same deisgn pattern, ie. fixed gantry with bed moving in one axis, similar to conventional CNC machines.

Hey kludgineer just to clarify, I do not consider this a Repstrap, just that it is uniquely suited for a Repstrap, I am still waiting to see the printable files my self. I rather like the design and I am waiting to see the rest of the details the MendelMax 1.5 is an excellent design and I don't expect anything else of this one. That asides, the cartesian robot is just about as old as the industrial revolution, I do not see anything surprising about the direction that the 3d printer robots are going towards. Delta robots are more interesting these days (also damn old).

I am hoping that the rapid prototyping might lead to more novel designs eventually potentially ones not constrained in build volume.

Maxbots

Thanks for putting up some pics of the 2.0. It looks good. I couldn't wait for it to come out so I got the parts for a 1.5. I can't wait to hear how your initial beta goes. Let me know if you need any more testers.

This looks really good. And seeing as though I was about to build a 1.5 I think I will hold on until this is out.

What do you think the build area will roughly be?

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kludgineer
If on the other hand you define "the RepRap idea" [...]

The RepRap idea is pretty well defined already. See e.g. [reprap.org] :

Quote

This machine, if successful, will be an instance of a von Neumann Universal Constructor, which is a general-purpose manufacturing device that is also capable of reproducing itself, like a biological cell.

and [reprap.org] :

Quote

The word RepRap is short for Replicating Rapid-prototyper. It is the practical self-copying 3D printer [...] - a self-replicating machine.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

A more practical definition is that a RepRap is a design which only uses off-the-shelf parts and parts that it can replicate itself.

So, having more custom-manufactured parts (CNC-milled or drilled, lasercut etc.) takes the design farther away from a true RepRap design.

Anyone know if plans or any cad/cam files are available for the Mendelmax 2? I have a Taig CNC setup and could make all the aluminum parts to get started on a build. I've been wanting to build a 3D printer to add to my shop and the 2.0 looks to be the most solid platform yet.
Thanks for the Info.

Apart from this [www.dropbox.com], nothing has been released yet AFAIK. You might keep an eye on the github [github.com]