Easy Road to Dimensional Accuracy?

I have been fighting some dimensional accuracy issues for quite a while.   There are is all kinds of advice out there as to how to go about doing it and I have only gotten about as far as to make sure that my printers are extruding the right amount of plastic!  Leaving that out as an explanation for parts that I print being out of whack by 2-4% in either direction!

Part of my challenge has been translating the advice from people that use other slicers into stuff that makes sense for Simplify3D which is what I am using.   So I asked for help on the user forum for Simplify3D.   Someone pointed me to an option called "Horizontal Size Compensation".  It takes a number of millimeters (+/-) as an input but frankly I was not sure how to use it...and assume that it would be better if I tried to calibrate things the "right way".

More fool me.  I finally decided to try it and found that it ... works?  Below are a sample of the results that I got on my first couple of tests:

 

The first test was for a spacer that will hold an 8mm nut.   As you can see the print without adjustments was too small.   The print with a -0.1mm compensation was perfect.  So I thought that I would try a bigger and more complex piece and printed a #3DBenchy with the same compensation not really knowing what to expect.  As you can see, I got the same kind of positive result.

Am I missing something?  It seems a little to easy.  This is a feature that has been in Simplify3D since I bought it a couple months ago (not just since the upgrade to 3.0) so I really should have tried it sooner.  If I had I might not even written my mean post about Simplify3D as that feature alone is worth the price of admission!

UPDATE

This setting is not the answer!  At least not for all cases.  I am finding that when I print a large-ish part in ABS, one that requires dimensional accuracy, there is some shrinkage that needs to be accounted for when the part is printed.  I have not measured this on the UM2 but on my D4S it is about 1%?!?!   I know that the printer is moving accurately as I have measured physical movement on the x-y dimensions but my parts are still too small.  I am finding myself doing a test print, measuring it, and then reprinting with an adjustment factor.

Never Has a Message Board Seen Such Truth

There was a question asked on the 3D Hubs Forum from a user thinking of getting into 3D Printing.  The below response has to be one of the truest of things that I have ever read on a message board:

"If you have never used a 3D printer before, then you are in for a shock, because 3D printing is really very, very hard beyond the simplest of things.  .... But I suppose as is the case with every printer, if you want really great results the greatest skill you need is infinite patience and print things really slowly." - Quoted from danilius in this thread from 3D Hubs.

Ultimaker 2 Print Quality - Simplify3D Profile

Finally got my Ultimaker 2 Profile for Simplify3D working to a level that I feel is pretty decent.  This version of the #3DBenchy was done at 150 microns at a slightly faster speed (40mm/s) than the post that showed the results from the Wanhao.  Again, it may not be totally perfect but I am willing to call it close enough, especially given the speed difference...but only for this resolution.  I still want to see this model done at the high level of detail that the Ultimaker is capable of doing.

The same notes as to how I got here apply from the Wanhao post, other of course, than the fan as the UM2 comes with one.

Here is the Simplify3D profile (Version 2.2) and following are screen shots of the relevant parameter pages.  Please see this previous post for some commentary on these pages and their settings. 

Note that THIS IS A WORK IN PROGRESS!  I am still tuning this profile. It is worth a note to say that as you lower your layer height and slow down speed for quality you may need to raise the extrusion temperature.   I think this is especially true at the sub-100 micron resolution that the UM2 is capable of doing.

Sould You Buy Simplify3D as Your Slicer

UPDATE - The below is relevant to Version 2.2 of Simplify3D.   I have just downloaded Version 3 and it does look to address a number of my rants.   In fact, as a new post will attest, there was a feature in Version 2.2 that I had never used until now...and is killer as described here!

UPDATE - As of August, 2015, I continue my love/hate relationship with this software.  The technical foundations of the product are excellent.  The slicer, the support model, the concept of a factory, all wonderful.   Some of the user interface still not so wonderful.  

The thing that irks me the most is the Version 3.0 feature that moves profiles from being stored in a user accessible file to meta-data that, on the Mac at least, is hidden from the user.  What is worse is that this meta data is subject to being lost if you do a reset of their software, or if it crashes and does a reset for you (this has happened to me).  To avoid this you have to remember to export your profiles as you make changes to them.   I have a lot of profiles.   Major pain in the ass.

What makes the above even more of a pain is the lack of attention to detail that is shown in many aspects of the UI for Simplify3D.   For example.   You can not export all profiles with one command and when you do select one for export the software does not carry the name forward to be used as the file name for the save.   This latter example, to me anyway, seems like the developer of Simplify3D is really only interested in the cool bits like the slicing engine and the support model.   All of their time goes into those aspects, and they are good, while the UI, at times, seems sloppy.  Tiny details that make a difference to the overall user experience.  I have complained about this to Simplify3D support but they have chosen to ignore me.

I guess the bottom line is that I would still pay for this software....unless there was an alternative that was as good as the core functions of Simplify3D.   I think there is a market there.
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Some months ago I bought Simplify 3D as the slicer to use with my new Wanhao Duplicator 4S.  I had been using Slic3r for slicing and Printrun to spool stuff to the printer and while I was happy with the combination I did take the opportunity to look at the options.

I came across Simplify3D as it is marketed by Wanhao though I did not buy it with the printer.  I had a little bit of a learning curve with Simplify3D but that was largely due to my wanting to use both extruders of my printer sooner than I probably should have!   The story of my efforts in this regard are a couple posts back in the blog.

So anyway, the good stuff about Simplify3D:

• It is an all in one package and is integrated under a pretty straight forward and understandable user interface.  
• The slicing engine seems to be pretty smart and while I have not time tested it against other slicers I do feel as if it may actually result in a faster print (than Slic3r for example).
• It has a really cool process based model where you can print multiple models at the same time with different settings.   This is useful across a range from calibration, to printing models with different tuning requirements, to using a dual extruder setup for printing in colors.
• The support structures that it prints are really well constructed (and easy to remove) and there is the ability to easily tune where the support is placed.

Unfortunately there are a pretty wide range of negatives some of which are surprising (or maybe just disappointing) for paid software:

• It is almost laughable given the reputation that IT has for "CTRL-ALT-DELETE" being a cure-all that Simplify3D has such a feature built in.  In the case of Simplify3D it is the "Rest All Settings" option under the "Help Menu".  I have had to use it a number of times when the software just seems to get confused.   Once was at the direction of support and most recently when my prints suddenly started to de-laminate at the junction of the solid layers and the first infilled layer.  Reset all Settings to the rescue and things were fine again!
• The system occasionally just crashes. This happens to all software once in a while but it happens with Simplify3D often enough to be irritating.   It usually happens when you have done something to a factory or profile and not save it yet! 
• The user interface needs a huge amount of cleanup.  It feels like an amateur wrote this code in terms of attention to detail and to the standards that one should expect from professionally developed software.   Some examples include, but are not limited to, the following (yes they are minor but I paid for this software and the free stuff that I am used to was, in many cases, less sloppy):
• Don't expect the tab key to take you to the next field on the form.  
• Don't expect a double click on a list to result in an implicit enter.
• Don't expect things to be remembered like the name of the profile that you have just loaded and want to save again.
• There are also features missing that really feel like oversights or flaws as opposed to things that we should have to wait for (again, examples, not a complete list):
• Button or menu item that causes models to be updated without removing and re-adding them (see Cura for an example)
• The processing model is great but it would be really nice if it would maintain order, or allow an option for order to be maintained, as this can be useful when doing dual color prints.  I know this might fly in the face of their optimizer which is why I suggest it as an option.
• Finally, there is functionality that I think should be there for a relatively expensive alternative to the world of free software:
• Explicit handling for multi material prints (not support, that is there).
• A built-in calibration process would be really ground breaking and could be a reason for some people to purchase for no other reason.

So am I happy to have bought Simplify3D?  Yes.  Though it sometimes frustrates me, I would probably still do it again.   Can I unreservedly recommend it?   Nope.   It is close to being really good.   Really great is attainable.   Some investment is needed. 

Duplicator 4S Print Quality - Simplify3D Profile

I am still tuning the Ultimaker 2 for best possible print quality but meanwhile the Wanhao Duplicator 4S is doing quite well.   Better than the Ultimaker 2 (which is close but still not where I want it to be)?  Who would have thunk it? I am sure that I will get there on the Ultimaker but for now thought that I would share these images.

This version of the #3DBenchy was done at 150 microns at a high quality generating speed of 30mm/s.  It may not be totally perfect but I am willing to call it close enough.

Here is a summary of the things that I have done to get the printer to the point of being able to print the above model.

Hardware

 

You may be able to print fine details in ABS without a fan but I am happy to use one as I think it makes things more reliable if nothing else.   The trick is to use a highly directed duct such as the one that I am using and is described elsewhere in this blog.

Slicer Settings

Of course!   The first area to focus on is temperature.   The lowest possible where you can still print reliably.  The second area that I spent a lot of time on was bridging.   I did a lot of tests to come up with the amount of filament to extrude without sagging and the speed at which it makes it from end to end without breaking and with adhesion to the ends.  

Finally, speed kills (quality).   The slower you go the better.   I us Simplify3D and I believe the default profile for the Duplicator 4S has speed set to 3600mm/m (or 60mm/s).  This is too fast even for draft work in my experience (strings).   The above print was done at 1800mm/m (or 24mm/s).  

Simplify3D Profile for Left Extruder - Right Extruder

Two notes on the above.  First, your results will vary!  This is what makes 3D printing so much fun (or frustrating).  Printer to printer and filament to filament and sometimes it seems day to day!  The other note is in regards to the left extruder.  If you are new to a dual extruder setup using Simplify3D see this blog entry.

Here are the profile settings if you don't have Simplify3D and don't want to wade through the FFF files.  There are also some notes below as to when I mess with some of these parameters.

Generally this setup works fine.  I do occasionally find a model were the wipe helps.  On some it hurts.

Some models call for two shells and two is usually enough...but occasionally three shells can look better (for example in hiding infill patterns)!

First layer of plastic goes down at 225 then we start dropping to our ultimate goal of 210.  You don't want to go there directly as the firmware will badly undershoot and leave you with no plastic being extruded.

First layers need heat to stick but after that it can result in a print with an elephant foot  (90 degrees should be enough to stck but hopefully not enough to melt).

The fan that I have on this printer is not hooked up to mother board.  For some reason Wanhao only started shipping their motherboards with the fan enabled.  Mine is not so I wired a fan from the power supply via a switch on the bottom of the printer.  In reality I run it 100% of the time unless I am really paying attention to the startup of a print.   That configuration renders the above page largely useless but for the top right corner where it becomes very important.  If you are doing a small print, or a large one with a pointy top, you want things to slow down.  Maybe even more that what I have here!

Decide on a speed here.  1200 to 3000.  I generally do drafts at 3000 but anything in anger at 1200-1800.  Couple this with thinking about the minimum layer time.

Don't usually mess with this page.

Zebra Stripes

Directed Fan Duct on the Wanhao Duplicator 4S

I had talked about the uber-cool fan duct that I am using on the Duplicator 4S some time ago but I thought I would share a couple more pictures of some print exaples.

Both Ships - Fan'ed on Right

These were both printed from ABS with a layer height to 0.2mm.

The differences are largely subtle but very much there.  Note the details at the top of the port holes in the bow and the top of the hatch to the cabin.

Note also the scortched plastic on the un-fanned ship in the photo to the right.  I am not sure how this would have gotten scortched as I print ABS at 210 degrees but it did and not on the fan running example.

No Fan Ship

Fan Ship

Back to "Only" Two 3D Printers

After 18 months of good service the Prusa I3 has left the building.   A kind gentleman came to collect it last night after winning a bidding war for it on eBay.  It was almost sad to see it go but I think it will have a nice home!  This post will serve as a requiem to the Prusa I3 as I encapsulate some key aspects of its operation for the new owner.

Prusa I3 Workflow

1. I use Sketchup as my 3D drawing tool as I have been familiar with it and find it easy to use for both 3D modeling and for other things like room design.  There are a lot of other tools many of which are discussed here.
2. Once something is designed and ready to print an "STL", or stereo-lithography, file is exported from Sketchup.   STL files are available from a number of sources and can be downloaded and printed easily.  It seems like the defacto source for 3D printable models is Thingiverse.  My stuff on Thingiverse is here.
3. Once you have an STL file you need to convert it to commands the printer controller will understand.   This is called slicing and results in a file of G-code commands.  A 3D Printer is basically a numerical control machine and that is the heritage of the G-code language.  The slicer that I used with the Prusa I3 was Slic3r.
4. The profile that I developed for the Prusa I3 can be found in the Prusa I3 zip file that is available here on Google Drive.
5. Once a G-code file has been created by slicing the STL file it is ready to print!  I use Printrun for this purpose.
6. Prior to printing the build platform on the printer should be prepared.   I use a paper towel with some window cleaner and a little acetone to do this.   I then spray the surface with a little hair spray as I have found this to work great for getting prints to stick!  Not all hair sprays are created equal so I use Loreal!
7. When the print has finished give it a couple minutes to cool and it should pop off easily.  A craft knife can be used if it is well and truly stuck.
8. Finally, a key part of my work flow from time to time has been to reach out to the RepRap community via the RepRap Forums for help!    The folks out there have been very helpful though sometimes they will ask you to read the manual!

Build Platform Leveling on the Prusa I3

1. The common leveling practice is to get the nozzle to within a piece of standard paper thickness of the build platform...uniformly across the entire surface.   You do this by measure at each corner and in the center.   
2. First, however, you start with getting the platform in approximately the right position using the center as your measurement point.
3. There is a knob located just below the x-axis stepper driver that tunes the position of the z-axis end-stop.  Turning this counter clockwise  causes the extruder to be lower and vice versa.
4. Once you have gotten the above adjusted it is time to work on the four corners.  They are adjusted using a Torx T10Hx50 to turn the bolt for the adjustment while you hold the thumb wheel as a lock.  Turning counter clock wise will lower the platform and vice versa.
5. The paper test, in my opinion, is only a starting point.  I use a bed level print to get the final level of adjustment.   There is one located in the Calibration folder of the files located on Google Drive (bedlevelwill.stl).  This is probably not a best practice but I have been known to adjust the bed while this calibration print is being extruded!

Prusa I3 Firmware

My Prusa I3 is controlled by a marriage of a Ramps 1.4 board with a micro controller, the Arduino Mega.   It is the Arduino that takes the G-code you generated above and translates that into commands for the stepper motors that are driven through the drivers on the Ramps board.   All this while the Arduino also monitors various inputs that also come by way of the Ramps board (three end stop detectors and two thermistors).   Heat settings for the build platform and for the extruder are also managed by this configuration.

All of the above happens under control of the firmware running on the Arduino.   My firmware of choice is Marlin and a copy of the configured firmware that is currently drive the printer is located in the Marlin folder of the files located on Google Drive.  Hopefully this will not need to be changed!  If you were to want to update the micro controller you would need the Arduino development environment.

The Possibilities of Ubiquitous 3D Printing

We are a little way from 3D Printing being ubiquitous but I am sure that day will come.  I am also not sure what form it will take, at least initially.  Maybe in a transition state between every home having one (aka Startrek Replicator!) the 3D Hubs concept will be the enabler with everyone in the world having someone like me nearby that will print their stuff for a small fee.

In any case, here is a scenario.  You just got your new 3D Printer and it came with a reel of filament.  In delightful blue.  You promptly order another reel in white but when you get it you notice a problem:

Sure enough.  That new spool is NOT going to fit.  Now in the olden days this would have had me making a phone call to product support and if they were nice they would ship me one that fits for free, maybe even next day shipping.   Or they would charge me for it at a margin of 60% and ship it pony express.   Or they would not have it in stock but would in a couple of weeks.  Take your pick.  In the new world you go search for Ultimaker 2 Spoolholder and download a design:

Then you print it:

Then you are done.   Two hours later and at the cost of 27 pence and some electricity:

In reality, I was not quite done.  The sharpest of bunnies out there might have noticed that the spool holder does not look long enough.   It was not.   So add a step of stretching it using a 3D design tool and then reprint it.   Another two hours and another 30 pence.

Obviously, I have a 3D printer.  But in that future world of ubiquity this could have been me printing the part for something on the printer down the street.  Or the replicator built into a cabinet in my new house as they are in most new houses.

Ultimaker 2 First Impressions

The Prusa I3 was to that junker of a first car that many people fondly remember.  Not dependable, not all that smooth at times, certainly not fast, but gets you where you need to go.  The Duplicator 4S was your first new car, maybe a Ford, or something like that.  Dependable, a little faster and a lot smoother.  When you finally got the beans to upgrade to the BMW you are now thinking Ultimaker 2.  Another thread of analogy...first computer assembled from parts, second computer a Dell, third computer an Apple Mac.

The Apple analogy is the one that I will run with.  Like an Apple product the Ultimaker 2 is certainly priced at the top of it's market!   It seems to be able to hold that honor through reputation that allows it to maintain top price.   I have not detected a cult as there is for Apple products but that may be part of the equation as well.

The packaging of the printer was solid, maybe not as glitz as a Mac product but it is only packaging!   First impression of the printer coming out of the box was of Apple like design and build quality.  It is a compact, sturdy, attractive little box.  Slightly industrial looking in a fancy sort of way.  There was not much effort involved in getting it ready to run.   Mostly just unpacking things and getting rid of some cable ties.  Assembly was pretty much just putting on the spool holder, mounting the glass build plate (a very nice piece of glass), and plugging it in.

When the printer powers on the inside LED's light up and the printer kinda glows.  Tres cool.  From a factory reset the printer comes up asking for a build platform alignment.  Pretty much the normal stuff here but done really well and pretty fool proof.   The printer then asks for some filament to be inserted.  Again, very straight forward and pretty fool proof if you are following instructions! 

Finally, I was ready to print some tests.  The instructions recommend using the included glue stick to prepare the build platform but I am a fan of hair spray.   From my previous printer I have a hood that keeps the hair spray from messing up the inside of the printer though I need to craft on that fits the Ultimaker.  The test objects loaded on the 4gb SD card that came with the printer all worked nicely.   Here is a picture of two of them.   

I also printed some of my own calibration objects and the results were really good.  Right out of the box it does the bridge torture test perfectly.   I guess I should have expected this but it was still good to see.  The printer is a keeper!