Is Bigger Really Better?

I hope to think so when it comes to engineers, as I’m 6’8″ tall!

But when it comes to 3D printers’ size really isn’t everything.

There are now two common selling points for those wanting to flog 3D printers – size / build volume and layer height.

And customers tend to assume they want the biggest unit possible, but want to print with the smallest layers possible, so let’s address these points below.

 

Build volume – The bigger the better?

After a pleasurable chat with one of our like-minded customers earlier this week we agreed on a number of misnomers, and they phrased one of them very concisely; “When shopping for a 3D printer customers often look for a spec. that will actually only fulfil 2% of their requirements, not the 98%”

I found this statement to ring very true, and build volume is a great example. Customers might occasionally want to print a large object that really does require a huge build volume, but 98% of the time the part they are printing will fit on a normal bed.

If you walk around the house and think of all the things you would probably want to print with your 3D printer – such as coat hooks, key fobs, door handles, light pulls, shelving brackets etc – you could probably fit each object in the palm of your hand, in which case, why do you need a build platform which is any bigger?

And yet still the natural first thought is to shop for a beast of a machine that is more expensive, ugly and domineering. Chances are the machine won’t fit on the desk, in the home or even at work, and 98% of the time won’t be used to it full advantage because there’s no need for such a huge space to print.

I’m not criticising as I’ve done it myself. After building my first 3D printer the next thing I did was build a much bigger one. And guess what? The big printer ended up printing parts that would have fitted on the first machine but just took longer to do and occupied more space in the office.

So to conclude, everyone might think they want a big one, they actually probably only need a small one!

Buddha_50mu_pencil_cu_2000

 

 

 

 

 

 

Layer height – The smaller the better?

Marketing numbers, the driving force for many product design briefs, are used to sell printers and grab the customers’ attention, and we are as guilty of this as the next 3D printing specialist. We quote a minimum layer height of 20microns and we are not lying!

In contrast to build volume, in the case of microns, the common misconception is that the smaller the micron the better.

But would you ever want to print using a 20micron layer height? Maybe, but it’s not the first thing to consider when starting a FFF print job.

The obvious payoff is time, if you have a few days to spare and don’t need the printer for other jobs you can get amazing results by opting for a 20micron print. But whereas it will take double the time to produce a 20micron print over a 40, the quality won’t be twice as good.

In fact, below 50microns the improvements in quality are difficult to justify and I don’t know anyone who has enough time on their hands to be patient and wait to see the results.

Tying up your printer for hours on end is not the only sacrifice with low layer heights. Design and testing is an interactive process; print three or four items in the time it takes to do one and you will find that everyone you print is tweaked from the last and you end up with a better designed part over the same period of time – this is one of the real advantages with a desktop 3D printer.

When selecting a 3D printer I would look for range as well as minimum layer height. ‘Draft’ is more often used than ‘fine’ in our office when selecting a print profile and starting a print; we might print a part five times before we are happy with the design and only the last time do we select ‘fine’ quality. Because of the twin nozzle system the Robox can print from 20 – 700micron layers, which we believe is an industry best (small boast there!)

 

In summary 3D printing is about gaining the ability to manufacture parts to your requirements on your desktop.

Most people don’t yet have this ability and it’s what 3D printing can do for you. Think about what you’re really going to make and where you would like to use your printer and select a product that fits that brief. For 99% of people, including me, ease of use, reliability and having something close to hand are the top 3 requirements, while print quality, features, future proof design and compactness follow closely behind.

We design products that we want personally, of course we have to sell them and play the same game as every other retailer or design house, but most of our design briefs are driven by personal desire. As with everyone we like to think that our requirements are not uncommon and so far feedback seems to support this.

Profile photo of Chris Elsworthy

About Chris Elsworthy

CEO, Design engineer, Family man, started product development company, best known for pitching CEL in BBC Dragons' Den. Robox and POWER8 workshop inventor. Portishead, Bristol · cel-robox.com

10 Comments

  • Profile photo of BHudson BHudson says:

    In my opinion, the selling point for 20 micron prints is the ability to make very small parts accurately. Once this layer thickness profile is refined, I think that Robox should be able to make some very small precision parts with very little cleanup. I am thinking parts in the order of 2-3mm on a side.

  • Profile photo of Chris White Chris White says:

    Hi Ben,
    You’re right – it would be great if we could print really tiny parts, but it’s another case of the right printer for the job. If you want to print really tiny things, such as jewellery, there are other printers on the market that are much better suited than Robox. The problem is that FFF printing is not really designed for really tiny things – although we have a 20 micron layer height, this only refers to the maximum Z resolution. In order to print tiny things with great levels of detail you require high resolution in all three axes, and when using the FFF process this is limited by nozzle size. Robox has a 300 micron fine nozzle (we believe the smallest commonly available), and an 800 micron fill nozzle, which means that the smallest feature you can possibly create is 0.3mm in diameter. If you wanted to print an object 2-3mm, that means you’d only fit a maximum of 9 or 10 nozzle diameters on a side, not really the kind of resolution you need for something like jewellery.

    Jewellers usually use investment (lost wax) casting to produce precious metal objects, and there are already a wide range of printers in the market which can print in wax or other materials which burn away cleanly when used as a casting pattern. SLA printers (which use UV light to cure photo sensitive resins) are much more suited to this process, as some are capable of an X/Y resolution of up to 0.1micron (OWL Nano) for example. Although these printers are more expensive, so are the objects you will be creating from precious metals, and therefore the resin/printer cost is justified – the same goes for applications such as dental. We want Robox to be used as frequently as possible without having to wait ages for parts, spend extortionate amounts on build materials, and to be used as part of an iterative process of constant design improvement (when used for prototyping).

    There are possibilities of reducing the nozzle size on Robox (no testing done yet!), possibly even as low as 0.1mm, but for the majority of users this would just mean a longer print time, and a quality level they don’t generally require as they’re not printing tiny things. As with most things, it’s a matter of compromise – price point vs quality, speed vs quality, build volume vs overall compactness, functional parts (useful) vs aesthetic parts (pretty) etc etc.

    If you want to prototype jewellery, I would suggest printing objects larger for design evaluation, and then scale down and produce the final object by making use of one of the many print bureaux out there that can print in a wide range of materials including gold, silver, titanium, stainless steel, brass and bronze.

    P.S. I’m sure you know all this already – but I thought I’d share for everyone!

  • Tryo says:

    While your insight is correct on build volume, that 89% of parts may be below a certain volume, I’d say the fact that I can’t do 2% of my parts is enough reason for not buying it.

    Because what is worse than a slightly larger printer, for slightly more money… is having to buy another one to print 2% of parts.

    • Profile photo of Pete Pete says:

      Or you could divide your part into 2 parts and print both parts separately with less chance of a total failure and wasted time.
      Most items in our lives have been designed with limitations imposed by tools, resources or time. A 3D printer is an amazing new tool, some are clearly better than others and each will have its own limitations. Our goal is to make it accessible to more people so we can all benefit from the combined experimentation of more people and improve the tools.
      Just being bigger might not improve the function of the part you want to print, maybe it would be better as 2 or 3 sections? Maybe it will even be easier to print if you divide it up.

      • Profile photo of Tom Gidden Tom Gidden says:

        It’s also worth noting that compared to injection moulding or other forms of manufacturing, with FFF it’s straightforward to integrate complex permanent joints to snap such parts together without adhesive or solvents… it might even be possible to have those joints added automatically as needed. With that in mind, the more important matter is small-scale detail to make those joins less apparent.

  • Tryo says:

    Well, let me ask this: can you use the build platform edge-to-edge? Or do you need to leave border?

  • Profile photo of Pete Pete says:

    The border is managed within the software. With the current bed design you can use the full build area without any change. I just tested this and all I had to do was clean the PEI sheet with IPA. I typically only use the middle of the bed so it had been neglected around the edges for some time.

  • Tryo says:

    I think you have an exciting printer, I almost slapped down my credit card the other night. But Im getting stuck on volume. I’ve checked my first prototypes, and I’ll need a minimum dimension of 9″ x 5″ x 2″ for my very first need. I could go catty-corner to get length on edge instead of flat, but then I hit the height restriction.

    I think many 3D printers have gotten mired in the trap of printing and demoing bobbles and trinkets. Unfortunately as we move to printing useful things, a bigger volume is important. And your printer enables fast and precise prints throughout the dual heads, making it a better fit for bigger volumes if not limited by printer volume. As I look around my office, as a microcosm of the designed world, a good 50% of the various objects I see are outside of the build volume in at least 1 dimension.

    So here is the question (besides I wish you have a bigger build volume). Can the nozzles reach outside the platform. and can a arched raft support the print beyond the borders of the platform?

  • Chris says:

    Great design. Next unit with a larger build volume, Ill fill my lab with them. I need 10″ x 10″ x 10″……. But everything else on this is like everything I could fix about my current printers in one well-thought out design. Props.

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