Review: Ooznest PRUSA i3

Introduction and the kit

Forget the glossy professional finishes of the latest 3D printers, the Prusa i3 is all about going back to basics and understanding where and how 3D print technology evolved.

This Ooznest kit is based on the popular Prusa i3 design and along with the latest stream of FDM printers such as the Lulzbot Mini, they all stem from the original RepRap project by Adrian Bowers, a professor at Bath University. His RepRap project aimed to create a machine that could replicate itself and would be able to make useful goods for the person who built it, so creating a symbiotic relationship.

DIY printer

The project itself is open source so anyone with a bit of knowledge or determination can build a RepRap inspired printer for around £350 or $450 (around AU$630). Not too shabby indeed. Of course, being open source the original RepRap plans have been taken and adapted, so many companies such as Aleph Objects have been able to produce their own superb range of printers based in some part on those designs.

In fact if you have the time you can download the Lulzbot plans along with all the source files to print the plastic parts, and you can then print out your own set of parts to build your very own Lulzbot.

The Lulzbot is a commercially available printer and while it is possible to follow the plans to build your own it can be a tricky. There are a few modifications to standard parts and the instructions can be a little vague, but then again they've put a lot of time and effort into fine tuning the original design into something that they are proud of and is commercially viable.

If you do want to build a printer from scratch then at present the most recognised update to the original RepRap design is the Prusa i3.

However, once you actually get started and take a look at building your own it quickly becomes apparent that it really isn't as easy as it seems. Firstly you'll have to spend hours tracking down all the parts that you need to build it – these parts in themselves aren't particularly expensive individually, but add postage and import duties and the price really starts to mount up.

Even then once you've gathered together all of the mechanical and electronic parts to build the Prusa i3 there's still a large selection of parts that need to be printed in plastic, with a 3D printer. So in order to make a 3D printer for cheap you need to have a 3D printer, or failing that a workshop and a whole bunch of tooling.

It is therefore much easier to buy a 3D printer kit such as the Ooznest Prusa i3, as if you take this route the hard work of sourcing the parts has been done. The full list of parts needed to build a Prusa i3 can be found here if you're interested and here's the original project.

Ooznest isn't the only firm out there that currently offers a Prusa i3 kit and it's certainly not the cheapest, but what becomes very evident once the kit arrives is that the guys at Ooznest really know what they're doing.

The kit

The kit costs £450 (around $690, or AU$970) and arrives in a large cardboard box, inside of which you'll find a further selection of smaller boxes all carefully labelled and tagged with the contents. Each box of parts is referred to in the build instructions, so as long as you keep it organised then the construction of the printer is relatively straightforward and no more difficult than building a Lego kit.

The instructions for the build are all located on the Ooznest website and are downloadable as a PDF, so you can actually see what's required from you before you buy the kit, and you can also check out whether you think you're up to the build prior to purchasing.

Constructing the printer

Build quality

Built around a metal framework and bolted together, the build quality really comes down to a simple matter of how well you can construct the thing, obviously enough. Ooznest has provided everything you need, so build it well and you'll get a decent quality printer, but rush through the process and the printer and quality of the prints will ultimately suffer.

As far as the parts go there are several key components that make up a 3D printer – namely the frame, electronics, extruder and hotend.

Starting with the frame the kit features a good quality pre-machined metal Prusa i3 frame to which everything – plastic printed parts, stepper motors, electronics and other components – gets bolted to.

At the heart of the printer is the RAMPS 1.4 control board which is the latest iteration of the board and a popular choice. This integrates the Arduino MEGA2560 board and stepper drivers and has a proven track record for reliability. The Hexagon all metal hotend and Bulldog Lite extruder are all really good quality parts especially at the price. This is a 12V setup that enables the use of 1.75mm filament through the Hexagon's 0.4mm nozzle, a great starting point that can be upgraded as you become more familiar with the technology.

Ooznest modifications

Ooznest has made a few modifications to the standard Prusa i3 design when it comes to its kit. Some of these changes to design have been developed by the Ooznest team whilst others are popular modifications made by the Open Hardware community.

These modifications make a big difference to the final print quality when compared with the original Prusa and include a Z-axis frame brace – two simple brackets that sit under the main vertical of the metal frame to ensure that the structure is square, and this helps to reduce frame wobble during printing.

To avoid any issues caused by bowed threaded rods, Z-axis isolators have been incorporated to keep the X and Z-axis separated, with a mechanical endstop also incorporated into the assembly which makes adjusting the Z-axis height much easier.

As with other Prusa i3 mods the power supply and filament reel are separate to the main body of the printer, and there are further mods that you can find on Thingiverse.com to update the Prusa i3. Of course these are parts that you can upgrade yourself once you have the printer up and running.

The build platform dictates the size of print that is possible once the printer is complete and this kit features a 200 x 200 x 175mm (W x D x H) build area, with the width being reduced by 5mm due to the bulldog clips that hold the Borosilicate Glass Build Plate to the heat bed. This size is on par with the Ultimaker 2 and Lulzbot Mini.

The combination of the Hexagon hotend and Bulldog Lite extruder enables temperatures of up to 295 degrees Celsius – this means that standard materials such as ABS and PLA are fully compatible. It should also mean that you'll be able to print with other materials such as nylon, although that hasn't been officially tested.

An LCD control board finishes off the design and this enables you to quickly adjust printer settings including fine tuning the X, Y and Z-axis positions, heat of the hotend, fan speed, and – if an SD card is inserted into the side – direct card printing. These are all high-end features that add to the ease of use.

Printing

Getting started

Once you've finished the task of constructing the printer which will take between five and 10 hours depending on your skill – our kit took around six hours to finish – you're ready to run through the commissioning and testing procedure, which needs to be done prior to the first print.

It takes around 20 minutes to go through the commissioning process with adjustments made using a computer and the Printrun software, and mechanically by tightening and loosening screws. Once endstops, fans and steppers have been checked and you've tackled the tricky task of levelling the bed you're ready for the first print.

Printing

Here Ooznest suggests using the Cura software by Ultimaker, which provides a solid and easy to use print interface, and again before use it needs to be calibrated for the Prusa i3 printer. Fortunately, when it comes to this process, Ooznest once again provides all the details making setup extremely quick.

With the machine added to the options and the model you wish to print loaded, it's then just a case of either attaching a USB cable to print directly or sticking an SD card into the side of the control panel to transfer the print-ready files.

It is at this point you see the limitations of the 12V supply, which obviously doesn't have the clout of the 24V used in machines such as the Lulzbot, so warm-up times for the heat bed and hotend are quite slow. Whereas the Lulzbot is ready to go from cold in around five minutes, with the i3 you can expect a good ten minutes wait or more to warm up.

However once up to temperature the actual print speeds are pretty evenly matched, with the i3 about 15-20% slower than the Lulzbot Mini with similar print quality settings. Here you also need to take into consideration that the Mini takes 2.75mm filament as opposed to the Prusa i3's 1.75mm.

The Cura software enables the quick selection of several different print qualities without having to reconfigure the printer. In our test each of these options printed good quality prints using the supplied ABS 1.75mm filament with little issue or misprints.

In the first week the printer required a little retuning every couple of prints, but once the structure had settled down and all rogue bolts were fully tightened print accuracy and reliability came close to 100%, and not too far behind that of the Lulzbot Mini.

Print quality is also surprisingly good and easily matches that of the Lulzbot for simple structures and models. However again there is a slight limitation with the finer filament and lower voltage when it comes to bridging and overhangs within structures. That said, a small upgrade and a little tinkering would easily enable quality prints that would rival printers twice the price.

Making a side-by-side comparison between prints from the Lulzbot Mini and the Ooznest Prusa i3 shows that the i3 just has the lead when it comes to sharp edges and fine detail, and this can be put down to the smaller nozzle and filament diameter. However, when printing larger structures with overhangs and bridges the more refined quality of the Lulzbot shines through.

Verdict

We liked

The big selling point for the Ooznest Prusa i3 is that you can build your own 3D printer. This kit also excels over other Prusa i3 kits due to its clearly defined boxes of parts and bags along with incredibly clear instructions on the building process.

The build process is great fun if you enjoy tinkering with mechanics and electronics, and you learn an incredible amount about 3D printing technology as you build. Handling, fitting and tuning each part as the printer comes together makes you far more adept at unravelling print issues and understanding many of the more technical aspects of 3D printing.

Once you've finished the build and start printing any preconceived notions about dodgy prints from self-build printers are quickly dispelled, and as long as you've followed the instructions and understood the processes, the end result is a device offering a print quality that rivals many printers that retail at twice the price.

We disliked

As with other kits based on the Prusa i3 design this is very clearly a homemade printer in every way. Our finished machine worked well, but despite producing good quality prints, the aesthetics of the printer or more accurately the neatness of construction left something to be desired. This is solely down to our neatness of finish when it came to tidying the cables.

Again as with the original design the power supply and filament sit separately to the main unit, and it would be nice to somehow integrate these with the rest of the machine. The manual is as clear as they come but once the build is complete a further section on upgrade ideas and projects would be a great way to complete the kit.

Final verdict

The Ooznest Prusa i3 is an incredibly addictive 3D printing kit. The build process is enjoyable from start to finish, and possesses enough of a challenge so that on completion you feel you've really achieved something, sparking a few head-scratching sessions along the way which are always overcome by simply reading the instructions properly.

The thought that has gone into this kit is staggering with high quality parts used where essential, as with the hotend and extruder, and cheap alternatives used for other less vital components such as the motor to threaded rod couplings. Money has been spent where it is needed in order to provide a basic kit that will produce good quality prints from the outset.

How good is a print from a homemade printer? Surprisingly good is the simple answer. Compared against two popular printers, the Ultimaker 2 and the Lulzbot Mini, the quality of prints produced by the i3 are closer to the Lulzbot Mini, with the Ultimaker 2 having the edge in terms of both quality and consistency.

The similarities between the Lulzbot Mini and Ooznest Prusa i3 really shouldn't be that surprising as they both come from the same origin, the RepRap design, and use the same brand of hotend, albeit with different voltages, filament and nozzle sizes.

No doubt with a bit of tinkering and an upgrade to the Prusa i3 the two would produce almost identical prints. As standard the Ooznest Prusa i3 is better at finer detail and sharp edges whereas the Lulzbot Mini is better at objects with overhangs and bridges, doubtless due to the larger nozzle and filament size, so there is a balance between the two as they both produce good prints but in different ways.

The Lulzbot Mini is twice the price, but if you buy all the upgrades needed to make a similar specification printer to the Lulzbot from the i3 kit, you'll have spent about the same.

Ultimately if you are looking to buy a 3D printer or already own one but want to know more about how they work then buy an Ooznest Prusa i3. The build process is thoroughly enjoyable and the amount you learn while making the thing is incredible. Buying a kit rather than sourcing your own parts is actually far cheaper and definitely a much less frustrating experience.

The level of thought that has gone into putting this kit together is incredible. Print quality is good and the kit should really be looked at as your first stepping stone into the world of real 3D printing, and once you're addicted there are plenty of upgrade options available to buy or print yourself.

from TechRadar: Technology reviews http://ift.tt/1PmmzsC