2014-11-23

Reviewing 3D printers

I've read quite a few 3D printer reviews over the last months and now that I have had the opportunity to collect two months worth of practical experience with a well known 3D printer, I have to conclude that most 3D printer reviews are worthless.

In general, you can disregard magazine reviews.  These are the worst.  The problem with these is that they are usually performed under time pressure and it seems more important for magazines to have a review of 3D printers than to do it well.

Magazine 3D printer reviews at this point are nothing more than glorified unboxing videos in text form and you should probably not take them seriously.   I say "probably", because sooner or later I guess some magazine will start applying serious evaluation methodology.  So far though, I have not seen this.

You will find the most useful reviews in blog postings and forums.  People who own the device and who have used it for at least a few months.   For example Nick Lievendag is pretty good at reviewing 3D printers since he actually uses them to do work.

Here is a brief list of what a proper review should minimally involve:

  • Test the machine for at least a couple of months.  It should have at least 350-500 hours of printing on it before you conclude anything.  If you think this is a lot: this is rather typical load when you do a project.  Prints take a long time so you try to minimize the idle time so that you can get more done per day.  50-60 hours of printing time per week is a relatively moderate load during a project.  You can easily double that if you time things properly and you have 24/7 access to the machine.
  • Test it until something breaks.  Some machines have weak parts.  You need to know which parts fail first and you need to know what it will take to repair the machine.  What is covered by warranty is really not interesting.  Breakdowns cause downtime and if you have to return parts and wait for new parts to turn up, that will cost you valuable time.  Also calculate the cost of running the machine over time given the cost of repairs.  (Some 3D printers need spare parts that add up to more than the printer costs within a year.  I have yet to see a single magazine review that addresses this rather important aspect of 3D printer ownership).
  • Take the machine apart and have someone with technical insight analyze the design and the parts used.  Down to looking at what chips have been used for stepper control, what CPU it uses, what kind of firmware, PSU, technology used for calibration etc.  Also get someone who knows about mechanical design to look at the mechanical design.  Precision, durability etc.  If you are squeamish about taking printers apart because you are afraid to piss off manufacturers, reviewing hardware is not for you.  If they try to make you sign NDA agreements you are, of course, disqualified from reviewing the product.
Taking the product apart is more or less a requirement for a serious Magazine review at this point. For privately owned 3D printers this may not be feasible, so it would be unreasonable to expect this from owners.  But people who make a living reviewing stuff:  if you don't you are not serious about what you do.

If you want to learn about tearing down products, I suggest you watch videos by Dave Jones.  He routinely reviews equipment and a standard part of a thorough review is him taking the product apart and analyzing what is inside.  Here's an example of Dave having a look at the GoPro Hero 2.

And if you are a manufacturer and worry about teardowns:  you need to learn how you can benefit from this.  Dave Jones tore apart a Rigol bench lab power supply a while back.  Which uncovered some design errors in the thermal handling of the product.  Rigol responded to this by fixing the problem, and guess what:  since they have fixed it and since Dave has had a thorough look at the product: people now feel safe when buying it.  Because they know it is a good product and that Rigol deals with problems.

PS: I'm in the process of trying to resolve problems with a 3D printer I use for work.  No magazine review I have read correctly reflects what I am experiencing and what other users I have met through forums are experiencing.  I am giving the manufacturer time to resolve issues.  At the end of my current project I plan to write a blog posting or an article about the product and whether or not the issues got resolved.  If the problems with the machine cannot be resolved and if we can't return it for a refund I hope I'll have time to tear it down and possibly rebuild the machine using different 3D printer components.  We'll see what I have time for.

2014-11-14

An open letter to Bayerische Motoren Werke AG

Dear Assorted Doctors and Otherwise Scientifically Certified Ladies and Gentlemen of Bayerische Motoren Werke AG,

I would like to humbly submit my suggestion for extensions of your current automotive control platform:  the Behavioral Adjustment System.

Now, first things first.  The acronym BAS might easily be confused with that of the Biblical Archeology Society and Bulgarian Academy of Sciences, both of which are organizations not to be trifled with, so I would hereby like to propose the marketing brand Bellendtronic for this system.

Well then, let's get into the details without further ado.  What I propose is a system that after three consecutive failures on part of the vehicle operator to engage the appropriate turn signal before commencing a turn, the car will initiate a Behaviour Correction Event.   A Behavior Correction Event seems best implemented by deploying the primary automatic occupant restraint system on the driver side.  In colloquial terms also known as "the airbag at the center of the steering wheel".

In order to not interfere with the safe operation of the vehicle (if safe operation of your vehicles is indeed within the operational envelope of your customer base), I further propose that the Behavior Correction Event not be initiated until the next time the car has come to a full stop.

Should the driver attempt premature egress to avoid the Behavior Correction Event upon bringing the vehicle to a full stop, I recommend the appropriate supplemental occupant restraint system be deployed.  Or, again, in colloquial terms: "punch the miscreant in the ribs with one of the side airbags".

Then deploy the primary occupant restraint system once the operator is forcibly realigned into the deployment zone of the aforementioned primary occupant restraint system.

I strongly believe that an addition of this system, as a non-optional extension of your vehicle control systems, will go far towards reforming your current customer base so as to make your fine automobiles a more attractive alternative to those who labor under the misconception that your automobiles do not include an operable indicator stalk.

(I have made careful field observations over three decades and according to my notes, which by now comprise a mere 5.9 metric tons of cellulose-based storage medium, indicator stalks are either present or have at some point in time been present in all of your automobiles.  Thus any statement to the contrary is obviously vicious slander).

I will have you know I have conducted extensive research into the feasability of this system.  Both the fellow I usually see making weak tea at the office caffeination station AND a local authority on extraterrestrial life forms (who is also behind innovations such as shaving off his eyebrows and drawing dual eyebrows in their stead using a 3mm sharpie) agreed that this was indeed a most worthwhile idea worthy of your diligent pursuit.  I can, of course, produce notarised statements from the aforementioned gentlemen should this in any way help speed your decision process along.

I would also like to inform you that I have no claims to the proposed trademark Bellendtronic, though I would urge you to secure the trademark swiftly as Audi have a gearbox operation system for which the same trademark would be eminently applicable.

Thank you for your serious consideration.  I look forward to the enthusiasm with which you will no doubt embrace my foolproof and, if I may say so myself, obviously brilliant idea.

-Bjørn Borud, inventor of society-changing things.  Well, at least up to the point where they make a sharp noise and emit festively colored sparks followed by voluminous puffs of acrid smoke.

2014-10-28

Breaking the patent system by making liberal use of patents.

It is no secret that I am no fan of patents.  Although the original idea was a good one (make sure inventions were shared), people tend to forget that the patent system was created a long time ago.  A very, very long time ago.  It is hardly relevant for the pace at which all industries move at today.

In fact, if you can still find an industry that doesn't have a high innovation pace:  that industry is likely to experience disruption in the near future.

Innovation- and development/iteration speed are just two underlying parameters that look nothing like they did hundreds of years ago.   But the most important parameter that has changed is that the nature of the predators that prey on those who want to make things.

It is now a legitimate business proposition to do absolutely nothing but collect patents and then extort companies and people without the necessary funds to defend themselves.

The top-of-the-foodchain-predator is today is either a solidly funded, large corporation with an army of patent lawyers, ready to unleash a heavily skewed justice system upon you -- or the patent troll.  Which is usually ditto well funded since they pick on the weak first to bankroll taking on bigger fish later.  People like Nathan Myhrvold, who already has more money than Croesus, but still takes time out of his busy schedule to shake down the weak and defenseless for money.

Despite having written a brilliant book on Modernist Cuisine (which I own), he is still a villain and I still think he epitomizes what is standing in the way of innovation today. (Funny how Microsoft bred so many, for lack of a better word, assholes among the top brass, yet the founder appears to focus on allowing his wealth to do the maximum amount of good...).

So one question that has been on my mind lately is "how can we help make patents more obviously irrelevant faster?".

I got the idea from a friend of mine who routinely studies patents to come up with solutions for his own, personal projects.

Personally, I try not to read patents if I can help it.  I'm shaped by working for companies like Google, where knowledge of a non-company patent is seen as a huge risk.  Were I to come up with something clever, I don't want there to be reason to believe that I was informed by existing patents.  I have thus far treated patents like I would treat seepage from a nuclear facility:  I have stayed far, far away.

But I think it may be time to re-evaluate that approach.  I think it might be time to encourage hobbyists and makers to make as liberal use of patents in their own personal projects as possible. And to freely share any information that may help other people implement patented technologies.

Like 3D models that can be turned into product.  I'm not sure you can be legally faulted for reproducing an interpretive work of a document, though I may be wrong.  And even if I am not wrong, the courts where patent predators do their litigation have a very strong bias towards the patent holder.

There are technologies that makes this feasible.  Like 3D printing.  And I am not talking about the current crop of hot-snot-dispensing FDM-printers, but stuff that you can use to print metal parts.   The stuff that a lot of startups are scrambling to get into the hands of consumers in not that many years.   If something is covered by a patent,  and if enough people manufacture the object themselves:  you might be able to put a big dent in the patent industry because it would be financially infeasible to go after the infringers.

Just look at the price of mechanical parts for cars.  Within short you should be able to print these at prices affordable to private citizens.  And eventually:  cheaper than the part sells for today.

A typical name brand turbo (which is a pretty hairy component to make) costs about $1500.  How long before you can print a turbo below that cost in the privacy of your home? 10 years?

The idea is to de-value patents by making it financially infeasible to take would-be infringers to court.   Both because they are so many and because most of them will have no assets worth going after.  For several classes of patents this is now possible.   Within short, this will be possible for more classes of patents.

Waiting around for (corrupt) politicians to sensibly reform, or better yet:  abolish patents altogether, is not a winning strategy.  It won't happen without significant pressure.  It is high time that pressure was applied.

And of course, lobbyists will attack the enablers for massive scale patent infringement -- by demanding whole technologies be subject to stringent regulation.  Well, good luck with that.

2014-10-27

Engineers and negativity towards making.

Over the past few years I've spent a lot of time tinkering and building stuff.  From electronics to mechanical things.  Both have been made possible by the fact that both of these things are now more available -- both in terms of physical availability, but also the knowledge on how to do things.  There are thousands upon thousands of blogs, videos, tutorials and forum posts on any DIY topic imaginable.  If you want to build something or solve a problem, chances are there are people who have published things you can learn from.

Tinkering, making stuff and learning new things has never been easier.

However the surprising aspect of making is the negativity I get from a lot of people who are, at least in theory, engineers.  It seems that it is extremely hard for a frighteningly large portion of engineers to understand why someone would make something themselves rather than just buying things.  Or why someone would want to learn about something that isn't strictly speaking required by their job.

Seriously!?

Of course, not everyone cares to figure things out and build stuff. I guess a lot of engineers, while nominally having jobs that require some creativity, would rather just punch the clock and do as they are told.

But I don't understand where the negativity comes from.

Norway has a problem with abysmal levels of innovation.  I think this shitty attitude might be one reason.

2014-10-21

Makerbot Replicator 5 gen lab notes.

For the past couple of weeks we have been playing with our Makerbot Replicator 5 generation PLA 3D printer in the office.  We use it for a project in the Exploratory Engineering department at Telenor Digital.   Exploratory Engineering is a program for allowing employees in Telenor Digital spend 3 months on a project of their own choosing.  The idea is that they get to do something that would otherwise be hard to realize, and at the end of the three months they pitch the product/project to management for funding.  Exciting stuff.

Mostly we use it to prototype enclosures for devices we are working on, but we also use it for printing various odds and ends that we need.

PLA plastic.

Previous to getting this printer I had mostly printed things using the older Makerbot products that use ABS plastics.   I had heard a lot of bad things about PLA plastics, but I have to say that it isn't that bad.  The parts are a bit more brittle and not as heat resistant.  On the other hand, the parts are much harder and more rigid.   It also seems that there is a lot less warping on big prints.  With ABS and early Makerbots I had to design and orient parts specifically to avoid warping, and it was always a nightmare with people walking in and out of the (heated) room and not closing the door after themselves.  Depending on your use this may or may not be to your liking.  For prototyping I don't find this to be a problem.

Extruder problems.

The extruder is the weak link in this printer.  Since you are using PLA, the extruder will clog sooner or later.  And chances are it will clog so badly you can't get it to work again no matter how many times you cycle it through unload/load filament cycles.

If you pick it apart I guess you will void the warranty -- but I would actually recommend you do pick it apart.  It is actually worth having to buy a new extruder rather than having to wait for 2-3 weeks for a new extruder to turn up.  If voiding the warranty is not your thing then I would advise against buying the Makerbot Replicator.

Thankfully, taking the extruder apart is relatively easy.  You have to be careful when opening the casing so you don't break the clips, but the insides are very easy to understand and to take apart. Beware that there is a spring inside which pushes against the nozzle at one end and the contact sensor on the other end.  The contact sensor is the little plastic thing with a magnet inside it.  It seems like the contact sensor actually uses a magnet and a hall-effect sensor -- which is a pretty clever design since mechanical switches aren't all that precise.

There is a video on youtube of how you do it.  The video is low quality, but it is helpful in showing you the order of operations when you pick apart the extruder.

Z-axis alignment before printing.

Before printing the Makerbot will go through a calibration procedure to determine the exact position of the Z-axis. If you have problems with the extruder rubbing against your build plate when it starts printing, it probably has misjudged the print plate position.  This will lead to the nozzle getting backed up and could end up clogging your nozzle.  You will hear a ticking sound come from the extruder, which means that the filament is slipping -- the stepper is pushing the filament but the filament has nowhere to go.

Sadly, the Makerbot doesn't have any configuration where you can adjust the Z-axis calibration and offset the print head, so instead you have to trick the calibration procedure.  What I've done is that I have 4 sheets of paper that I have cut into a long strip;  when the printer starts its pre-print Z-axis calibration I slip the sheets under the nozzle as it measures the build plate position.  Then, before it starts printing, I retract the paper again.  This way it will start printing at a slight offset over the Z-axis and it won't grind the nozzle into your build plate.

It seems that if you print things on a raft, the extruder will start a bit higher and pump out a thicker extrusion on the first pass and that this lessens the chance of getting a Z-axis problem -- but this is just guesswork on my part.

Wishlist for Makerbot gen 6

  • Make the extruder user-servicable.  It will clog and it will be more expensive to engineer an extruder that guarantees you won't have clogging than to make it user serviceable.  I wouldn't even bother trying.  Get rid of the fragile clips, at least for the main housing, and use proper torx head bolts.  Provide instruction videos for how to pick it apart.
  • The calibration/measurement sequences are slow.  Dead slow.  This smells of bad programming rather than a conservative approach.  Levelling the build plate shouldn't need to take more than 30 seconds.  The pre-print Z-calibration should be a 5-8 second affair.  I have no idea why it steps down so slowly when lowering the extruder to the plate to trigger the touch-sensing.
  • Make the firmware more configurable -- both up front and during printing.  Things like travel speed, temperature, Z-axis offset etc might as well be configurable.  If people screw up then they screw up.  (Being able to adjust travel speed while the printer is working enables you to find good settings faster since you don't have to start an entirely new print).
  • Document the network API of the Makerbot so users can easily write software for interfacing with it.  Give it a proper REST API and put libraries for different languages on GitHub. Encourage third party developers to make libraries.
  • Redesign the build plate guide and attachment.  It has a tendency to not slip correctly into place.
  • Fix the top of the extruder where the filament guide tube attaches to the print head.  It has a tendency to slip out and taping it in place doesn't work well either.  I've been thinking about designing and printing a kludge for this.
  • Make all the values editable in the print profiles.  Sure, most people who care are fully capable of editing the JSON file with the config values, but having a proper UI for doing this would be nice.
  • Make it more hackable again.  The product isn't a traditional consumer item anyway, so you might as well go back to your roots and design the thing to be user-modifiable.  If it voids warranties:  fine, I can live with that.  I'd rather risk breaking the bot and have an easier time repairing it than being guaranteed humdrum performance.