[Mr.Chips]

Is there a link where I can find a comprehensive discussion of the pros and cons of the different approaches to the design of a 3D printer?

I've built a couple of CNC machines, the last running on all linear bearings which I am very happy with, however because of the low loads and mass that is dealt with in 3D printing these types of bearings are not needed a simple bushing bearing is adequate.

I like the unique design of the RoStock and are interesting to watch but there is a lot of movement on all posts to make any movement of the print head, while the standard XYZ axis designs might only be moving on one axis.

This said, do the RoStock designs wear out faster because of all the movement?

Thanks
Hager

[awerby]

I'm not aware of any threads like that, but you could start one, either here or on a site devoted to 3D printer discussions. The first thing to decide is what sort of 3D printer you want to build. There are quite a few different approaches to choose from, before you get into details like Cartesian vs. delta designs. As well as the most common FFF (fused filament fabrication) type, there are some based on photo-catalyzed resins (SLA and DLP) jetted polymers (Objet) or powder beds with jetted binders (ProJet), SLS (Selective Laser Sintering of polymer or metal powders), paste extruder systems for building things from clay or concrete, direct metal deposition, and a lot of others too numerous to mention.

[schmutzig]

If you're new to the world of 3D printing I wouldn't recommend a delta printer design to start off with. They are difficult to configure and have a lot of gotchas like the print resolution is dependent on the location within the bed area and most use a Bowden tube design which is finicky and less accurate than having the motor directly on the extruder. What delta printers have going for them is they're fun to watch, they can be less expensive to build than other designs, and they can be built with fewer parts (since several of the motor and axis assemblies are symmetrical).

I used a printer with a Bowden tube extruder for several months and recently abandoned it. The printer was very unreliable and the overwhelming majority of the issues were the Bowden tube itself and jammed filament or failed prints because the extrusions weren't accurate enough (lots of small isolated shapes). Positional accuracy is important and so is extrusion accuracy. Backlash isn't acceptable on any other axis so I'm not sure why so many people accept it on the extrusion.

[dharmic]

The first (and only) printer I've bought personally was a Rostock Max (the first ones).

If you can swing a spanner, turn a screwdriver, strip/twist/tin and solder a wire and crimp a connector and you can pace yourself and pay attention to details along the way then you can build one of these beasts no problem.

The calibration of them is a little tedious but, really, it's an hour or so to do and then you're up and running.

They bought a Create3D cartesian printer at work and it was fun to play with for a while, but I gotta tell you, if I need a print to work properly it's back to the Max. Bigger build volume, fast, accurate. There are pattern artifacts in the surface finish caused by the delta calculations and there are some tricks to getting good bed adhesion on large prints, but really these aren't a big issue.

The motion on all three axes to do anything is similar to using your mill to bore a pocket - no problems at all, it looks crazy but it all works.

There are a few who've made deltas with linear bearings but I personally think they are massive overkill. The standard carriages in extrusion are just fine.

Bowden tubes caused me some issues at the start until I learned the trick of loading them completely with no slop in the PTC connectors and, since then, I've had zero problems. Setting retraction correctly (speed and length) eliminates backlash.

If you're looking at deltas, the support from the Rostock owners' community at the SeeMeCNC forum is unparalleled. One of the main reasons I chose the printer and I have zero regrets.

As far as other formats are concerned, I rejected DLP style resin printers because the parts they print just don't have the strength and they are slow. Layered powder based printers, again, lack strength. They also have the hassles of dust everywhere to contend with, although they do have the advantage (some of them) of multi colour and no supports required. Laser sintering systems are pretty damned sexy - especially the metal ones that carry the powder in the shield gas stream - but they are stupid big bucks. There's some good reasons FFM printers are so popular.

[stargeezer]

I've built a number of printers and have played with a few designs. Here's my opinion list about each style;

Mendel Pursa I3

A step above the pursa with all it's threaded rods and adjustments. The kit I built had an aluminum frame and bed support and was fairly strong except the O frame had a noticeable amount of flex front to back. I added a couple braces that helped this. It came with a J head extruder and a Wades style feeder, both of which worked fine for PLA.

Mendel Pursa

This was the one that started things rolling in the 3d printer world and like the stone axe, it has a place in history. It may have been the single most flustrating thing I've ever built.

Mendel Max v1.5

I've really come to like this design with a few updates. There are more printed parts than some other printers but they are readily available. Here is the one I've built MendelMax 1.5 ZX2 by jmwalsh - Thingiverse I've got the third one on my bench right now and I'll build another after it for a nephew. It is solid construction, very stable and using a E3d extruder and a wades clone feeder it's dependable.

Ord Bot

I'd place it between the I3 and the MendelMax 1.5. It's a good design that can easily be expanded or shrunk down. The part count is less than the MM 1.5 so it might be cheaper to build except it uses wheels and extrusions that are a bit expensive. They function great and will give you a very acceptable print. Not as stable as the MM 1.5, but not too bad. I've built one and I MIGHT build another.

Crane Style Printer

I can only say that I have a unfinished one in my workshop that I'll get back to some day. It's a fundamentally weak design that I think I might be able to stiffen to an acceptable level - someday.

As I said,, this is all my opinion after building a number of printers. You and about anybody else may have a different opinion and thats why there are so many to choose from. Good luck my friends.

Larry