Replacing LinuxCNC with a Smoothieboard for CNC milling. Not as easy as for 3D printing!

I was running LinuxCNC for the last years and I wanted a smaller setup, with room for improvement. Since I had a Smoothieboard around, which is a very capable 32 bit ARM controller for 3D printers, I thought it would be a good idea to give it a try.

A bulky, obsolete but usual milling setup with a PC running LinuxCNC (a parallel-port is required),
versus a Pipo X8 which is interfaced to a Smoothieboard (hidden in the CNC driving box itself).

But the move is not a piece of cake when you expect a drop-in replacement. In fact, I must admit this board is somehow hostile as a firmware for milling in its current status (Smoothieware), even though the hardware is fully capable (Smoothieboard). In this post, I wanted to share my experience so far. Sure I could have asked for help (and yes, I did RTFM eventually). But it takes time, it will not solve the issues below and I think most people would have done like me: just try, then investigate.

With time, I think it may be sorted out, probably with help from others if they are welcomed (and hopefully without breaking more mill bits). But my expectation here was to benefit from Smoothie as much as one can benefit from it for 3D printers. Even though my current overall hardware setup is much convenient and lighter, the milling process ends up requiring more manual and careful operations than before. More annoyingly, I would end up having to tweak and modify an existing CAM tool just to handle the specific "milling behaviors" of this board. I would think that the reciprocal would benefit everybody though.

3D printing nozzle characteristics

Nozzle shapes and nozzle materials

Obviously the nozzle diameter is one of the major parameters when 3D printing. But you may have wondered about the many nozzle shapes that are available on the market. Some brands have preferred shapes. And, even though will not have a drastic impact on the print, they may be significant and worth a post.

Overall length of the nozzle?

Marketbot vs Ultimaker nozzles.
Both are quite long, but the former has a
bigger flat ring around the nozzle hole.

In my opinion, long nozzles are more convenient for cleaning, and they let more cooling air flow around.

Shorter nozzles reduce heat loss a bit and they probably give a better control and reading of the temperature (remember: the sensor is on the heating block, not on the output).
They could arguably help to reduce the overall length of the hot end, so they reduce could positioning error slightly. And they may spare a few grams... But this is marginal and for the most hard core players: they will not help make a bad design better!

Being a contractor or a full-time employee?

Working as a contractor versus regular employment?

I regularly see the fear about working as a contractor. Lately I was part of a discussion that started like: could it be risky for any subsequent 9-to-5 career? I strongly disagree: being a contractor is interestingly a warranty for me to find again a new job in case I fail as a contractor! In my opinion, it will indeed help most careers, as I an employer I would favor people that took the risk to try, whether they were successful or not. Contracting both provides and requires skills at the same time, more than any regular 9-to-5 job.

I feel like I can handle all sorts of professional blows, like being fired. And first of all, well, I will not be fired as long as I am my own boss! This is because I feel each day insured by varied and evolving professional experiences together with a growing professional network.

Here is a post about how I ended up as being a very happy contractor, after having been a state employee, a full time engineer in a small family-owned company, then in a stock-valued much larger company, then a CEO and a CTO in a start-up (silly names), and a very well-paid part-time employee in a startup... before I flew on my own in the naked simplicity of a contractor in a cooperative, with no mess.

Disclaimer: my experience is all in the so-called "new" technologies, but it may still help beyond.

Messy code, branches with a lack of guidelines and comments are killing Marlin!

Marlin no more exists as a single, readable, common branch!

Where shall I go now?

In a previous post, I described a tiny contribution I made to the 3D printer firmware Marlin. The deal was to help with the calibration of a Delta printer thanks to a manual Z-probe (calibration really is the drawback of Delta printers, due to their weird geometry as compared to easier cartesian X-Y bots like the usual printers). It was already painful for such a small, one-time improvement to the code source, and given the invested time, I tried to make it broader by implementing multi-line comments (and to learn about git by the way).
http://www.dailymotion.com/video/x2gp98t_hal-fixing-a-light-bulb_fun

This is how I feel when I want to code something in Marlin!

(Malcom in the Middle, fixing a light bulb)

So I worked in mainstream Marlin. My idea was that it could benefit to existing variants of Marlin as well, when they decide to get changes from the "official" parent. But it does not work so well in reality.

This experience unveiled another, deeper, issue related to the many Marlin variants, and I think it is due to the fundamental way github works, in addition to git own complexity. In my opinion, Marlin is just dying because of this, together with the limits of the Arduino platform.

Headlines again... 3D printing guns, a passion?

Headlines again: 3D printing yet another part of a gun. So what?

Please Cody, yes, you the guy with big stainless-steel thermoplastic bollocks, please, now I want new stuff, like 3D printing bazookas, ammo or landmines!

I already tackled the subject it in this older post but telling that a 3D printer is probably not the best tool to use is not even my point here. Using a 3D printer to print more guns is no surprise, but I wish headlines focus more on noble usage like e-NABLE prosthetics. It is an excellent project, where volunteers 3D print free upper-limb prosthetics, like artificial hands for others. If your printer is idle, you should go and read about them!

E-NABLE: is this not a better use for 3D printing, according to you?

This way we have people printing tools that may harm people, while other people do repair them. Nice absurd world.

Here is my point for once: why do the words gun and freedom have to be put in the same sentence almost each time pro-gunners start to argue? What the heck?

How to use Openscad (4): children and advanced topics

Part 4/5: children, factorized placement and chained hulls

Yes, it was made with Openscad and it is parametric!
(extreme collaborative work, picture by N.Goodger)

Previously in this tutorial for the Openscad CAD software, we talked only about modules that behaved as shapes.

A powerful and often ignored feature of Openscad is that modules can also behave as if they were operators, exactly like the translate()or color() operators. They do not create shapes on their own, but they modify the subsequent commands.

In Openscad, it is possible through the use of children. But first, let us create and discuss a bit about a common-case example.

How to use Openscad (3): iterations, extrusions and more modularity!

Part 3/5: iteration, extrusion and useful parametrized CSG techniques

Repeating shapes

As we saw in the previous article, repeating a shape by copy/pasting its Openscad definition is a bad practice. It increases the risk of mistakes just because of the slight changes that have to be made on each of the copies. And any "regularity" should be factorized: let the computer do our work!

The former way we built a (partially) rounded cube. Four copy/pastes? Boo!

See how the four columns really are all the same cylinder, where only the position changes? This is where we can and we should use loops instead. And once again there are different ways to do so.

Fortune 500 teller? 3D printing trends, reports, analyses and business intelligence...

Are the "high-level strategically analyzed reports" worth something?

Hey, could my blog be so informative? :)

I am regularly contacted, mostly on linkedIn, by experts that seek data. The last time it was for a company that compiles data and trends "for the Fortune 500 companies". Which does not excite me more than that, and here is why.

Such data are usually sold at an incredible price to managers that think they would get a better clue at the market, with the idea that they would be more profitable. But there are two traps here.

The first one is: am I really enough of an expert to give clues to Fortune 500 companies? I am mostly an iconoclast, e.g. when I say not to invest in Makerbot at all (neither as a customer nor as an investor, but I have a full-length analysis why I say so), or when I explain why, imho, "pro/expensive" FDM printers are almost a scam nowadays. OK, I may be better than a monkey and provide a few useful reviews (e.g. materials for artists, or what cannot be 3D printed...). But still, asking my opinion on the market trends could cast a doubt on the forthcoming corresponding report. Oh, well, may be they also want data from makers -- why not after all.

As a manager, do you really need accurate trends and data?
Or do you need only the feeling that you have some?

Secondly and as importantly, the reviews are most often never used in reality. Once bought, they are dropped on the desk of a subordinate in the company, with the advice to get some insight from the document. The underlying idea is: since it is expensive it must be valuable...

How to use Openscad (2): variables and modules for parametric designs

Part 2/5: Variable and parametric design

The previous part addressed the basics of Openscad. It relied mostly on "immediate values": we were providing dimensions as explicit numbers. If you want to tweak the design dimensions, then you need to parse the scad source code and fix the numbers all everywhere.

In fact "hard coded" numbers must be avoided. As opposed to "static" designs, parametric designs give the flexibility to tune the numbers very efficiently at one place only. The good point is that Openscad is one of the best tool to do so.

A larger mug by using the scale operator (from the "basic" tutorial).

This is still not parametric, as numbers are hard-coded (a bad practice).

See how the numbers in our mug design above depends on each other? If the cube is to be made taller for any reason, then the intersecting sphere and hollow cylinder must be tuned accordingly in the source code. And this is exactly something a computer can do better than us.

So let us first convert this design to a parametric version, i.e. a design that can be tweaked with a small set of parameters that all have a clear role (width, height and so).

How to use Openscad (1), tricks and tips to design a parametric 3D object

Part 1/5: Introduction to constructive solid geometry with Openscad

Some technical and non-technical people keep asking me how I create new designs. As often, after a few personal replies, I end up heading to the blog to share the answer as they keep asking for more.

Also, I long wanted to write a pragmatic and step-by-step introduction, howto and tutorial to Openscad. The idea is to help people even with no programming skills (mostly in this part) and to bring newcomers to a point that they can design their own 3D objects (part two). Interestingly, Vicariously, Openscad is very interesting to get a glimpse at what programming is because you get an immediate, visual feedback of your actions (even my mother, a former history teacher, was eventually able to get a clue at what my job was about). Once understood these concepts, it may be much easier to move to other languages.

Now, if only a few readers become "designers" by reading this I will be quite happy. If some people realize that programming is not that obscure I will be happy also. Meanwhile, I will have given a detailed answer to my friends and contacts!

A non-obvious GoPro mount of mine, that is fully customizable thanks to Openscad.
It looks complex, but it is still exclusively made of spheres, cylinders, and cubes with a few basic "joints".

A forthcoming last part will deal with the complex features of Openscad. This one is for people that either learn fast or for those that are already proficient with the usual features of Openscad.

1. Introduction to constructive solid geometry with OpenSCAD
2. Variables and modules for parametric designs
3. Iteration, extrusion and useful parametrized CSG techniques
4. Children, factorized placement and chained hulls

So first, what is Openscad? Within the CAD family, it is a 3D modeler: a software that helps you to create 3D objects. There are many such tools, but this one is used extensively in the 3D printing community, not only because it is free but because is it really efficient for some kind of objects.

It may or may not suit your mind, but with time I am able to "see" the shape I describe, not as text but directly as shapes. I guess it depends on people, but I am sure there are people that are not programmers that can think alike. And if you are already a programmer with no industrial goal then you really should give it a try. It will be a breeze to use up to a productive level, especially if you do not want to invest time in a new and hellish interactive user interface!

The official manual is OK but it does not really work as an introduction. The navigation is also sometimes difficult to the point google is more useful. There is a nice raw cheat sheet also but it has no link to the respective functions (what a pity!) (update: it does now!). In any case, these fail to help to learn Openscad quickly in my humble opinion.

E3D v6 hot end: ideas and assembly tricks

Assembled E3D v6 with a few particularities

You may remember that I wrote broadly about hot ends in an another post, but this short new one is specifically about the sixth revision of the E3D family (E3Dv6).

This is probably the best hot end on the market right now (in my opinion -- and I did not check them all). It is not cheap, hence expensive as all the good quality hot ends. But this is a critical part where you cannot really lose money if you value your time...

However there are still some room for some improvements. 

Materials for artists: 3D printing wood, chalk, and eventually metal with bronze

Important materials for artists

An amazing door knocker by Sonia Verdu
(rust comes from post-processed glued iron dust)

Still today, the visual quality of 3D printed objects is far from perfect. Of course, a stringy or bumpy surface does not mean the part will not work: you can get a visibly ugly part that still works well enough as a mechanical connector for example. But an artist will certainly not like it.

This post tries to list the main filaments that artists would look for first. Many other filaments are listed in a former post about materials that can be printed (without artistic consideration).

It also talks about the brand new bronzeFill filament from ColorFabb. Yes, it does contain bronze. No, we are not yet printing metal really. But certainly it is a major and very welcome addition to the list of interesting materials to 3D print.

Why you should not buy Makerbot 3D printers!

Avoid Makerbot and its 3D printers, they are both wrong.

Really! And there are many reasons not to buy: cost, reliability, human values, innovation and so.

I endorse even less Makerbot business
than I already trusted their products !
But enough is enough, this time I say why.

Seriously, Makerbot Industries care more about money than 3D printers. They so badly want your money that they start using dirty business practices. As a client, their overall strategy is simple: you will increasingly pay more to get less. The quality of the product does not count as long as they keep selling it through marketing tricks.

Update (nov. 2014): eventually, well-known resellers of 3D printers like imakr even stopped selling them because of after sale burden and heavy customer negative feedback.

Update (april 2016): interestingly, this post still holds. Makerbot just moved its production to China. A few arguments may be outdated though, so read carefully.

Do not think this is a biased joke, neither only a maker's rant (as formerly). I really want to warn would-be customers that they should not buy. And I want to try and stay objective.

But beside this, Makerbot brutal business strategy makes all this clear beyond doubt. I cannot think of any other motive than greed, or may be also for the inflating ego of Bre Pettis, its director. By the way, 3D printing certainly never was invented by Makerbot -- this is pure usurpation. Please do not fall in the trap of old and dirty business practices.

3D print fair at Fabcon 2014: feelings and people

Fabcon 2014 - was worth 2575 kilometers and 31 hours on a motorbike!

So I was kindly offered to give the closing talk of the 2014 edition of Fabcon 3.D in Erfurt, Germany.

My talk is now available online as slides, and also as a youtube video (for some unknown reason I cannot embed it here).

Note that I added a short separate post that resumes it, with a few new ideas: The businessman and the maker. This one is about the people and projects I met there.

My spoken English should definitely be improved (and I was half sick half exhausted), but it will spare you pushes on the space bar for the next slide, and more importantly, you still get details in the 25 minutes not-so-lively speech. My apologies, as it was the first time I spoke in public for years (back to my time at the long-gone Palm company, and more significantly during my PhD, huh, 14 year ago!). Please read ahead.

Quick comparison: pro versus low cost FDM 3D printers

Are so-called "professional" entry-level 3D FDM printers worth their price?

A LinkedIn user in my network asked for more data when I said that "low cost" FDM printers could compare favorably to "professional" (and expensive) printers. Sure, it is a bold statement, and it does not hold for every of the many "levels of quality", as there are just too numerous. But let me get into more details.

In my opinion, an Ultimaker rev. 2 (~2K€) compares very nicely to a Stratasys UPrint-Se (~23K€)

I certainly do not want to say the "pro" printers are crappy, nor that any brand is crappier than the other, but I had the chance to compare my Ultimaker prints with a "professional" Stratasys entry-level printer (i.e. 1200€ versus 23K€). The outcome is that I just would never swap the two even if I was offered the "pro" one for free! Huh.

Now I am a power tinkerer, I know how to print, I prototype the printer itself, and I cherish freedom, but I tried to keep this bias out of the following arguments.

Thoughts and hints around hot ends

This post finally documents ideas and hints I had during the design of two hot ends I made last year.

My extremely small "cheesy hot end" (all-metal and actively-cooled), here with an Ultimaker printed support.
This hot end was very easy to make (only used basic tools) and also because the barrel is quite short.

At the time I already had ordered an E3D hot end, but the lead time was so big that I decided to give it try myself. Actually, since I attached it with this tiny E3D support on my Ultimaker, I almost never swapped my hot ends anymore because it is just so reliable... The only drawback is that the efficient heatsink could be made almost half the size for more Z space, less vibrations and less weight (hence my smaller, low cost --and low quality-- copycat by the way, see below). And it does not mean I stop thinking ;)

How to 3D print nylon and trimmer line reliably: do not dry it too much and glue your bed!

How to 3D print Nylon reliably, cleanly and hassle-free.

A well-printed and robust dual-head Nylon mount (check it here).

Nylon is flexible, slippery and incredibly tough when it is printed correctly.

For me, it is a cheap and very useful material to 3D print. It is my best choice whenever PLA is not possible, and the very reason I never use ABS (more about the materials in this post).

But the nice properties of Nylon are the ones that precisely make it difficult to print ! By the way, Nylon also produces toxic fumes when heated, just like ABS, so it better be used in well-ventilated rooms.

I tried many known and unknown techniques to print reliably, and it is time I share my experience because I am happy with what I found.  Read on for more!

Fixes and howto for the DIY Fabscan 3D scanner

The fabscan is cheap... but it can be made to work.

For my curiosity, I bought a DIY "Fabscan" to try scanning small objects cheaply.

Update (2016): this post is very old. Many bugs were fixed since and I was told most of the improvements I list below were made in between. So make sure to get the latest software and doc from the official website, even before reading. And better even: the project is still active!

And it proved to be cheap, in all the possible ways.
In my opinion, the most annoying thing was the totally unusuable FabScan Ubuntu Live CD software.

This post is mostly about how to get it to produce an STL with the Ubuntu Live USB distribution specifically made for the fabscan.

3D printing with a smaller nozzle diameter

For sure, a smaller nozzle produces finer details,
but how tricky and troublesome it can be!

Is it worth using a smaller nozzle on a 3D printer?

I changed my hot end after my experiments with cheap nylon trimmer line, and it happened I had a 0.3 mm nozzle around. Was it worthwhile for even finer prints?


True, you can / do get finer details... but once again, there are trade-offs. And as for me, I will still mostly use a larger nozzle for the reasons I explain below.

3D printing with cheap Nylon trimmer line/string

Is filament quality so important after all?

I heard years ago that trimming line was one of the many materials that was tested on a 3D printer (the biggest list is probably here). This time I tried for myself, and it was also the proper occasion to deal with how "reliable" the material has to be (note that I wrote another post more specifically on how to print it).

Really, trimmer line may be a fully compatible filament !

My hot end is dying: the annoying PEEK thermal insulator started to melt (I suspect that the PID regulator overshot the temperature because of intermittent connection that I have fixed since). Still, it does not impede the flow much, so it gave me the opportunity to try some risky fun : what about this basic nylon trimmer line I got for free 10+ years ago when I purchased my gardening trimmer tool?