VynZ Modern Life

All things modern.

RepRap Ormerod: 3D printing Ikea style

Evaluation of options

There are so many 3D printers on the market these days it is difficult deciding which one is right for you.

The first consideration is what additive technology is appropriate for you as they all have advantages and disadvantages. Looking only at affordable commercially available printers, your choice is between fusion deposition and liquid acrylic photopolymerisation printing. Fusion deposition is the more established technology and there are more models available. The PLA or ABS filament required by these machines are widely available in many different colours, are relatively inexpensive and their physical properties are well known. Raw material for the liquid acrylic printers however are more specialised and available only from the printer supplier. Therefore unless you need the resolution of photopolymerisation printers, stick with FDM and save loads of money.

Next, decide whether you are actually interested in the technical side of 3D printing of you just want to get printing as fast as possible. If you belong to the former category, there are many open source printers that are available in kit form which require assembly. Although this can be quite time consuming, the advantage is that if you are technically inclined you will be able to have full control and make modifications to suit your particular needs. There is also the added advantage that these kit printers are usually relatively inexpensive compared to the fully assembled versions.  Fully assembled printers are ideal for those who simply require good quality 3D prints immediately. Again there are many options and they will typically cost between two and three times the price of a comparable kit printer. Many printer manufacturers also now supply units with varying capacities for print volume. The more you pay the bigger the object you can print.

I chose to buy the Ormerod model made by RepRap. A new version known as the Ormerod 2 is the current model and some of the differences are covered in the last section. I decided that the Ormerod was the best printer for my needs for the following reasons:

  1. The Ormerod was the cheapest available and this was the primary consideration.
  2. Generic filament can be used which is readily available on the internet at cheap prices. For me this was the second most important factor.
  3. Not afraid of assembling and commissioning as I am used to this.
  4. Ease of maintenance. Moving parts are easily accessible and are mostly generic meaning that spares can be found cheaply and easily.
  5. As an open source project, upgradability is a definite possibility. In fact there are loads of upgrades that you can buy direct from RepRap.

Mechanical construction

The printer arrived well packed in a little cardboard box. It is also quite light. In fact, if you were looking to move your printer a long distance from the point of delivery, for example a foreign country, this would be ideally packaged. Step one consisted of unpacking the box and checking the contents to make sure that all was there. However when confronted with the sheer number of parts, I decided that it would be best to check as I went along. In the end all was there except for two acrylic spacers used for mounting the duet control box.

IMG_2211

Figure 1 – Ormerod parts unpacked from its small box.

Some claim that the printer can be assembled in a few hours. RepRap staff can do it in just over four hours. It took me two days and I am fairly accustomed to assembling scientific equipment. The entire assembly process is adequately detailed on the RepRap website. There is also a very good time lapse videos on YouTube, which gives you a very good idea about what to expect. There is no need for me to go into it in detail but I must point out that the kit arrives completely in pieces with very little pre-assembled. I mean you literally need to assemble every little tiny bit. You will need loads of the correct tools, a large clear space and there will be lots of small parts that can be easily lost or broken during assembly. There needs to be quite a bit of very precise filing, cutting, trimming and crimping to get it assembled. Remember, one mistake and the machine will not work.

IMG_2213Figure 2 – You will need THIS much space to assemble the printer.

IMG_2223Figure 3 – Because it will soon be looking like this.

IMG_2216Figure 4 – Assembly of the basic frame is quick enough.

It is by no means an easy assembly unlike say, building a desktop computer, but this makes finishing the job is all the more rewarding. Be warned though that you need to be already quite adept at assembling mechanical and electronic parts. If you are not such a person or lucky enough to have a lab full of tools, I can see this becoming quite a nightmare.

Commissioning

Once the hardware is assembled, the next step is commissioning and generating your first print. This involves getting the machine and several pieces of software to communicate and talk to each other. This software is all free but must be downloaded from the right place and be of the correct version to all work together. In many cases the correct version is not necessarily the latest version or even the most obvious one. In addition, each bit of software has its own quirks of operation which just need to be learnt. For me, the most difficult part of the entire project was going from assembled machine to first print. This process took about two weeks and was incredibly frustrating. In the end, the problem turned out to be that the slicer produced an incompatible retraction speed and this caused the Ormerod firmware to crash. Bear in mind this was using the recommended slic3r profile.

IMG_2353Figure 5 – For commissioning it is best to leave the cover off as the operation of the board can be assessed using the LEDs.

Recommendations

During the assembly and commissioning process, I got the distinct impression that this machine was for people who had more of an interest in 3D printing itself rather than actually using 3D printing for their work. Once you get printing, do not upgrade firmware or software unless there is some new feature that you absolutely want, or have a lot of downtime to play with. As soon as you upgrade anything the whole problem of different versions of software talking to each other rears its head. There is also no guarantee that your new software is going to be more reliable or even as reliable as your old software. The same goes for Ormerod firmware itself, do not upgrade the firmware unless you have read the instructions a few times over and checked the forums for problems. You should also absolutely need some new feature. For example one firmware upgrade actually changed the use of an electrical pin which required a physical change to the circuitry which wasn’t even mentioned in the upgrade instructions. I just happened to notice the relocation of the wire in a photograph posted on the forum.

There are also a few quirks that you need to remember to live with. Due to it’s design, the Z-height proximity sensor will always be inaccurate. Not only is the calibration process quite tricky but it seems to be affected quite badly by ambient light. When doing the bedset routine, best close all windows or otherwise try to block light falling directly on the bed. Z = 0 should then be set manually so that the first layers print properly. The sensor on the new Ormerod 2 now works in a differential mode to help alleviate this problem.

The supplied print bed is extremely flimsy and because it is made of MDF, it warps under its own weight. It is best to replace the bed components at once with stiffer beams and a laser cut aluminium bed which can be found on online auction sites. I never got reliable prints with the stock bed. The Ormerod 2 has a different bed setup but I cannot comment on its suitability and it still looks like it’s made of MDF.

There is no tension adjustment on the Y axis. This is the motor and pulley system which moves the print bed to and fro. You set the tension when you attach the belt and that’s it. There have also been reports that the threaded rod which lifts the print head up and down (Z axis) wears out very quickly. I found that this was the case after only a few prints making this upgrade as well as new stainless steel rod and nut necessary. It also helps to keep the threads well-greased or there will be noises.

The fact that this printer consists of many 3D printed parts means that it is relatively easy to manufacture. The drawback is that where precision or rigidity is required (e.g. attaching the vertical and horizontal beams) the printed parts leave too much room for error. These joints can never be set up accurately resulting in the axes never being exactly aligned. To overcome this, several software and measuring techniques are used to compensate. This however relies on an inaccurate z-height sensor as well as measuring a test piece with a rudimentary screw gauge (which you need to print) and putting the error into a compensation instruction. This method of compensation ends up compounding lots of small errors and is so bad that the compensation is actually better done by guessing,

If you are looking to get printing quickly, this is not the printer for you. Spend a bit more and invest in a ready build model from one of the competing companies. As I actually need to print 3D objects for work, I don’t think that I would buy another kit like the Ormerod even though I have been able to tinker with it and do some upgrades of my own. The time required for assembly and the ongoing issues makes it more of a 3D printing enthusiasts toy that an actual working tool.

Advertisements

One comment on “RepRap Ormerod: 3D printing Ikea style

  1. Pingback: 3D Printing – Ormerod 1 | VynZ Modern Life

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Information

This entry was posted on 16 February, 2015 by in Technology and tagged , , , , .
%d bloggers like this: