Editor's Note: This is the first in a series of articles written by Daniel Halvorson discussing technical topics around how to produce higher quality 3D Prints.   The example prints shown in the article were printed on his Printrbot Simple Metal in colorFabb NGEN Silver Metallic.

There are two main opposing types of errors that can produce poor corners: ringing and corner swell. To achieve high-quality corners, certain parameters must be matched to the printer’s physical characteristics, and they must be balanced to avoid falling into either of these errors. Before reading this article, check out the explanations for Ringing and Corner Swell. Here, we brush up on the causes of these errors and the functions of the parameters involved, and in the application section, the solutions will be explored.

Theory:

A printer’s maximum corner quality is ultimately limited by two main characteristics: ringing is allowed by the rigidity of the nozzle’s positioning, and corner swell is allowed by the stored compression in the extrusion system. For more information on those two, see the definition pages for Ringing and Corner Swell.

With these physical characteristics in mind, the relevant software and firmware settings are speed, acceleration, jerk speed, and those relevant to extrusion pressure.

Electronics: Speed and Acceleration Control at Corners

To understand the solution for balancing ringing and corner swell, we must dive into the processes behind how the printer’s microprocessor and stepper drivers choose to make the printer handle corners.

In an ideal world, a printer would be able to change directions instantaneously. However, since this cannot happen in real life without the printer being subjected to unnecessarily high forces, causing extreme ringing, there must be a short deceleration period applied before the printer encounters a corner. The slicer and microprocessor both know this, and account for this deceleration before the corner and acceleration after the corner.

If programmed deceleration/acceleration values were the only method a printer used to navigate corners, the nozzle would slow down to a complete stop at every acute corner. However, anyone familiar with a printer’s behavior knows this is not usually the case. If you recall the cause of Corner Swell, you will remember that there is stored compression in the filament between the drive gear and melt zone. This causes a small amount of extrusion to continue at the corner, when the speed has momentarily dropped to zero before the nozzle accelerates out of the corner. If a printer intentionally slowed down to a stop during direction changes, the corner swell would be exaggerated.

If the printer doesn’t decelerate at all when going around a corner, there will be extreme ringing and possibly even overshot steps. But if the printer decelerates all the way to a stop at every corner, there will be extreme corner swell, and sharp corners will be impossible. How can the printer avoid falling into either of these extremes?

It turns out that paradoxes like this are pretty common among robotics applications where stepper motors are used, so much so that these systems have a simple little trick up their sleeve—so simple and reliable that the user rarely sees it. It’s called maximum jerk speed, and it represents the highest speed that the microprocessor assumes the printer can decelerate to and accelerate from instantaneously. (Even though the term “jerk” is shared with the formal physics concept of the third time derivative of position, the two concepts are quite distinct from each other, so it’s important to recognize the differences. Maximum jerk speed is indeed a speed, and printers typically measure it in mm/s.) This is a good compromise: the printer doesn’t hit a corner at full speed, so ringing is manageable; yet the printer doesn’t slow down to zero, so corner swell is minimized. The maximum allowable jerk speed tends to have a larger impact on ringing than acceleration does.

So how can we use these concepts to improve print quality?

Application:

Rigidity and Accuracy: Ringing

The more rigid a printer’s structure is, the less capacity it will have for ringing. The first solution is pretty simple; get out those tools, square the printer up, and tighten it down, with some appropriate Loctite for good measure! To take it to the next level, the frame of most RepRaps can often be stiffened with printed gusset plates and such.

Proper belt tensioning is also important. Tensioning belts with inline springs that clip onto the belt is not recommended, because it introduces a huge amount of springiness into the position of the nozzle. The best tensioning systems are those that use one or more pairs of captive nuts and bolts, which allow you to precisely choose how tight you want the belt to be, and adjust it in precise, small, repeatable increments. Some printers come with these systems, but if yours doesn’t, you can find numerous printer-specific designs in various online file repositories, or design one yourself.

Extrusion Pressure: Corner Swell

All other things being equal, the lower the compression in the filament between the drive gear and melt zone, the better a printer will be at avoiding corner swell. Keeping the backpressure low by using a clean nozzle at a sufficiently high temperature is one of the only quick changes you can really do to a given printer. That being said, if you’re using a softer filament and you’re experiencing an undesirable level of corner swell, you can switch filament types to something more rigid, like PLA.

Electronics: Speed and Acceleration Control at Corners

This is the crux of this article: how to balance between a printer’s tendencies for ringing versus corner swelling. There are several reasons you may want to tweak this balance. Different models of printers (even different printers of the same model) usually have different optimal balances between the two. Or perhaps you want to specialize: maybe you mostly print structural parts that need sharp corners, but visible ringing isn’t a cosmetic issue; or maybe you’re printing figurine models at low speeds and low layer heights and you’re more concerned about reducing ringing at all costs. Well, the procedure for adjusting these variables is pretty straightforward: talk to your printer by connecting to it with any program with a terminal. (Octoprint, Repetier-Host, and Pronterface are common ones.) Enter the command M501, which asks the printer what some of its settings are (the ones stored in EEPROM). XY jerk speed is the one you’ll mostly be interested in. For Sprinter, Marlin, Smoothie, and Repetier firmware, the command you’re looking for is the X parameter of M205, “advanced settings.” The most common scenario is that you may want to adjust your printer to reduce ringing at the expense of slightly increasing corner swell, and you would do this by noting the current value for M205 X_____, subtracting a bit, entering it with M205 X[new value instead], and then saving it to memory with M500. Conversely, to reduce corner swell at the expense of worse ringing, increase the maximum jerk speed.

As an example, I printed two single-wall squares from identical g-code, identical in every way except that the printer’s EEPROM value for XY jerk was intentionally weighted toward producing either ringing or corner swell.

 

The print shown below from two angles has high ringing, but insignificant corner swell, as you can see. It was printed with very high jerk speed.

 

In contrast, this print was printed with a jerk speed of zero mm/s, and as you can see, it exhibits considerable corner swell (but has no visible ringing).

 

That's all, folks! Shoutout to Trevor Ward for his helpful feedback. If you have any questions, contact me. And as always, stay tuned for more articles arriving soon.

If you are active on any number of Facebook 3D Printing groups, there's a good chance you've had a positive interaction with Daniel Halvorson.  I'm active on a lot of those groups, and I've noticed how good Daniel's advice usually is.  Not only does he offer good advice, but he is usually very respectful and polite.  Knowledgeable, helpful, and polite is such a rare combination in social media that I had to approach him to compliment him.  

As we got to talking, an idea was born.  Daniel would take his knowledge and use the Printed Solid blog as a platform to share his advice.  He came up with the idea of establishing a series of articles for A Solid Foundation for 3D Printing.  These articles would go through some of the basic concepts required to really produce great prints.  If we get it right, they will be presented in a way that has enough technical depth to satisfy more experienced users but enough simple information that newbies aren't scared away.  

Here is Daniel's introduction:

Hello, everyone! My name is Daniel Halvorson, and I’m an engineering student going into the field of additive manufacturing. Matt Gorton and I are kicking off a series of articles that will explore the engineering side of hobby-level 3D printing. Over the next few months, articles will be posted periodically to the Printed Solid blog. Whether you’re a garage tinkerer hoping to avoid design pitfalls as you build a DIY printer, a student learning about the theoretical intricacies of printing, or a hobbyist who’s focusing on the practical side of print quality troubleshooting, I hope there’s something here for you.

If you have ideas for new articles, get in touch with me! Likewise, if you feel that something could use more clarification or should be explained differently, or if you see a typo or think something is incorrect, don’t hesitate to contact me.

Happy printing,

-- Daniel Halvorson

(You can find me on Reddit and Instagram as “techyfiddler”, or you can usually reach me quickly on Facebook.)

www.facebook.com/techyfiddler

Daniel Halvorson

**Sorry about the wall of text.  Working on some interesting pictures, but had a few people asking and wanted to get a draft posted.  Feel free to message me to poke at any aspects so I can correct.**

 

Home user?  Design, slice, print, wait...  wait...  POWER OUTAGE!  swear your head off.  Start from the beginning.    

Happened to you?

Institutional user?  Student comes to you with a print, you start it, then realize that the day is almost over, there are still two hours left in the print, and you're not allowed to leave the printer running unattended.  

Sound familiar?

3D Printing is awesome, but sometimes things go wrong.   A few printers have after market add ons or software modifications that give you the ability to resume a print after a failure or to resume a print after a power cycle.  What can you do if you need to have an extended pause or resume a print after failure if you don't have these features?

A few months back, our friend Vicky of TGAW3D published her solution to this problem.  Her method involves Simplify3D software to generate the code and connection over USB to determine the object height.  It is a great method if the specific set of conditions apply to your situation.  

A few weeks ago, I had the opportunity to come up with a different method.  I'm sure I didn't invent this method since it seemed pretty obvious after the fact, but it was new to me, and I figure it might be new to some of you as well so I'm sharing.  

Here's the scene:

It was a stormy day at Printed Solid HQ.  We were busy running all the printers preparing for Dover Comicon 2016.  The weather looked so nasty that I had superstar summer help Jack run extension cords all around so that the printers running longer prints were on UPS.  

 

We were printing a Tardis on the Lulzbot Mini and cool stuff on all our other machines.  

The storm ended and it was time to go home for the day.  

There was no power outage and no power surge (perhaps thanks to the UPS).  I walked around turning power off on all the printers...  including the Mini that still had only about 15 minutes left.  AAARRRGHHH!

I immediately realized my mistake and confessed what I had done to Jack.  Then I turned the lights out, locked the doors, and went home frustrated that I had lost all that printing time.  

During the night, I reflected on what Vicky had done in her video and decided I could save that print, but I hadn't sliced it in Simplify3D, so I couldn't quite use her method.  

In the morning, I tried out my method and it worked great.  I didn't document anything at the time, but I've recreated the scene on the Ultimaker Go.  

Here are some instructions to repeat what I did on your printer.  

0)  Before doing anything, manually set the bed temperature to whatever it is presently at so that it doesn't pop the part off the plate  i.e. If the bed is all the way down to room temperature, leave it there.  If the bed is still sitting at your printing temperature, leave it there.  If it has fallen to some random number in between, leave it there.  

If the build plate has cooled down to room temperature, do not heat it back up.

Reason for this is that every time your bed changes temperature, it stresses the interface between the bed and the bottom layer, which will make it more likely for your part to pop off.  (as an aside, one trick for removing a really stubborn print is to heat and cool the bed several times)

1) Measure how tall the incomplete print sitting on the bed is.  Using the depth gage on calipers is a great way to do this pretty accurately.

{insert picture here}

2) Open your gcode in a text editor and search for the z-axis move nearest to what you measured.  You have a choice here.  You can either choose to go to the exact number (if you find it) or one layer below OR one layer above.  Going to the exact number or one layer below will potentially give you a small ridge in your part whereas going above will likely give you a weak point.  In most cases, you will want to choose the exact number or one layer below.  Choose wisely.

3) Copy all text from the line identified above all the way to the end of your code and paste it into a new file.  

4) Add in the following lines at the beginning of the code:

M17 ; engages the steppers

M200 DXXX ; Where X is your filament diameter.  *ONLY INCLUDE THIS LINE IF YOUR PRINTER USES VOLUMETRIC EXTRUSION, SUCH AS WITH AN ULTIMAKER*

G92 E0 ZX; where X is the z-height of the line selected in step 2.  This will tell the printer that the height the head is currently sitting at is X.

G28 X0 Y0; this will home the printer in X and Y direction.

M109 SX; where X is the temperature you are printing at 

G1 E6; this will purge some filament from the nozzle

M106 S255; This line will be unnecessary in some slicers where your fan speed is adjusted with layer time or by feature type.  This assumes you are running PLA at full cooling.  If you are running a different material, adjust to a number between 0 and 255 to reflect % cooling you are using.  

Now save this file as something like OLDFILENAME_RESCUE.GCODE

5) Now you need to adjust the nozzle height so that it is approximately at where you want the print to resume in the z-direction.  Do this using either the move menu on an LCD or via USB control in your control program if moving via LCD isn't applicable to you.  Or you can just manually turn the lead screw.  After you've moved the nozzle to the correct height, leave it there.

6) Load the code you've generated onto your printer using SD, upload, or whatever applies to you.  

7) Press print.  If it doesn't purge out some filament prior to moving over to the part, turn the power off, check your code, and try again.  If all is going smoothly, stay at the printer through the first few resumed layers just to make sure everything is going OK.   

8) Bask in the glory of not losing all that filament and time!

9) Wait for print to complete.  Remove from build plate.  Take a victory lap around the room, and then tell everyone you can think of how awesome you are for saving that print.  

 

I'll end this with a caveat.  There are some printers that will not tolerate this method and some that may require further post processing steps.  For example, the Makerbot derivatives using the X3G file type need the gcode to be converted into that format and some other printers have their own proprietary formats (boo!) so be careful and try not to be too dissapointed if this doesn't work for you.  You may also find some funkiness with autoleveling setups depending on exactly how the print failed. Maybe you can take the idea and improve on it for your machine.  Feel free to comment if you've done so I can add your machine specific tips to the writeup.  

 

 

 

We’ve been spending the last several months working hard to get our new warehouse and showroom ready to open.

On May 15th, 2016 from 10-4 we will be celebrating with an Open House and Maker Festival and YOU are invited.  Our showroom and the entire warehouse at 2850 Ogletown Rd, Newark, DE will be open to the public for this event!

If you want to help us know how many people are coming, please RSVP at event brite.  It is free. 

Printed Solid Show Room and Warehouse

Here is some of what we will have going on.

  • All the products you see at PrintedSolid.com will be on display.  Interested in Bronzefill, but haven't been able to convince yourself to make the plunge and buy some?  Maybe you think you want a shiny new BCN Sigma 3D Printer, but don't want to make the jump without seeing it in person.  This is your chance to check everything out.  
  • If the stars align, we'll have our a brand new Lulzbot Taz 6 sitting for your evaluation and to take preorders.  
  • DOOR PRIZES!  We'll be giving out a number of cool things including free class sessions and printed things.  
  • Free samples.  Our friends at colorFabb have donated free samples of NGEN filament to giveaway to attendees with printers.  

Meet some cool people at our Makers Festival

Special Visiting Guest:  Joel Telling from the 3D Printing Nerd YouTube Channel.

Joel has been a friend of ours for a while now.  When he heard we were going to be hosting this event, he wanted to be a part of it.  So, he’s going to be flying out all the way from Seattle to come for a visit.  Stop by to meet him and maybe get a 15 minutes of fame in the video he films of the event (or not if you are shy).

Learn about 3D Design

A representative from Morphi, the easy to use ipad 3D Design App will be present to give demonstrations.  Learn how you can easily create your own models for 3D Printing!

3D Printing in Education

We are huge proponents of using 3D Printing as part of education.  We've worked closely to help several schools in the region develop strong programs and have also helped many schools throughout the USA select the right material for student projects.  Josh Ajima, author of the excellent DesignMakeTeach blog will present some of his work.  Local educators will also be on hand to talk about how they use 3D Printing as part of their curriculum.  

 

3D Printing in Engineering Use

3D Printing has a huge amount of value in engineering.  It allows ideas to be quickly evaluated.  Some of the materials we carry with improved mechanical properties allow some users to even print parts of functional machines on their own printers.  Most of the time, these applications are proprietary to the companies doing the work, but competitive robotics teams can be great examples of this application. 

The Flaming Phoenix Robotics FTC team will be on site to demonstrate their competition robot.  They have made heavy use of 3D Printing on this machine. 

Another application is using the 3D printer to print other 3D printers!  This is known as reprap and is really the birthplace of all of the consumer grade machines we use.  John Abella will be on site demonstrating RepRap printers. 

 

3D Printing as a Creative Outlet

Alright, I’ll admit it.  A lot of what you’ve probably seen with 3D Printing and a lot of what we show at our table is simply things that look cool.  Hey, I'm a mechanical engineer and have spent most of my adult life working on functional things.  Part of what I love about 3D Printing is the ability it gives me as an engineer to produce artistic works that would otherwise be outside of my reach.  

We’ll have two 3D Printing artists on site.  Vicky Somma and Cole Hastings.  We’ll also be showing off some work from Chris Milnes.  Here are some examples of their work.

TGAW 3D

Creative works by Vicky Somma

Some 3D Printed Pop Art from Chris Milnes

3D Printing Medical Applications            

3D Printing has become very popular for printing prosthetic arms primarily for kids who quickly outgrow expensive purchased prosthetics.  Not only does this allow children who might not otherwise have access to prosthetics to have them, it allows for customization.  Our friend Aaron Brown is an active member of the organization E-Nable and has designed numerous character themed arms for kids.  Check out this Wolverine themed prosthetic (it's OK mom, the claws are only decorative).

wolverinehandx

In addition, 3D Printing can be used to help visualize anatomy to help doctors prepare for surgery. 

We’ll be featuring an example printed arm as well as example printed anatomy. 

 

What are the kids making?

4 Youth Productions will be showing off some of the work they have done with kids in arts and technology.

Mike Carroll, author of the Dewey Mac book series will be on hand with books and Detective Invent kits.  

Facilities and Groups to Access More Making Tools and Expertise

Sometimes you have a project that is more than you can handle on your own.  Maybe you need access to expensive equipment, space, or expertise that you don’t have.  Or maybe you just want some camaraderie from other like-minded people.  That’s what Makerspaces are for. 

Wilmington based Barrel of Makers as well as Lancaster based Make717 will both be on hand for hands on demonstrations and to talk about what is available in their organizations. 

 

 

 

I had a great time attending Midwest Reprap Fest 2016.  It was a lot of fun to meet online friends in person and see the amazing work that reprappers are doing. 

For the most part, I was only able to get away from the table at the beginning of the day before many people got there, so more pictures of things than people, but here are a few.  Will get some more up when I am back at my home PC, so check back later in the week to see some more!

 

 

The following is a guest blog written by Kyle Mohr.  Credits at the end.  

Kyle had approached me through a friend of a friend (said friend being a SeeMeCNC Rostock Max V2 owner and the one who printed Kyle the awesome MIDI box) about wanting to try some of the colorFabb wood filaments on his new Davinci printer.  I have some personal experience with the Davinci printers and know that there are some nuances with the way that the machines I had tried operated, particularly their startup routine which lets the filament sit hot in the nozzle for an unusually long period of time during some long cleaning motions and bed heatup.    

So, I encouraged him to start out with some samples, be prepared for some nozzle maintenance, and asked if he would be willing to write about his experience.  I was very surprised to hear some of the details from the XYZ customer support call, particularly that the nozzle couldn't be removed for cleaning!  

 Here is Kyle's writeup.  

DaVinci XYZ Pro meets colorFabb

As a musician, DJ, father and homeowner, I’ve had my fair share of DIY projects ranging from building DJ MIDI controllers to refinishing wood furniture.  As a natural progression it only seemed that 3D printing was next on the list.  Almost a year ago I built a 16 button MIDI controller with help from my friend who 3D printed the wood enclosure (made with colorFabb BambooFill from Printed Solid).

After sanding, staining, soldering, and tediously programming, this thing looked, felt, and smelled like I hollowed out a block of wood.  To say the least, this is when my obsession began.  I started customizing other gear, relying on friends to make me prints with STL files I emailed them the day before.  I knew it was time to make the dive and purchase a 3D printer myself.

When it came down to it, I did not have $1,500 to $2,000 to shell out for something legit, and being a complete stranger to the 3D printing world I looked into the daunting world of cheap, unreliable, low-grade printers, just to get the job done, for now.  Then it happened; upon looking into the recommended XYZ DaVinci 1.0 and JRs which seemed to be the best low-price all-in-once printers I could find, XYZ announced a pro version open to 3rd party filaments, and it had a laser engraving option…meaning I could print in wood and laser engrave it, I was sold. 

Black Friday hit and that sucker was mine for something close to $550.  Quite the steal, at least I believed.  I purchased it through amazon, since every gift card helps!  I waited patiently and it finally arrived, I unwrapped the beast and got to work, with my bright magenta (pink) ABS filament which was packaged with it.  Not my choice color to work with, but I didn’t feel as bad wasting it on test prints.

After a few months of tests, random deice knobs, and an Apple TV mount, I was ready to graduate to some non-XYZ filament.  I contacted Printed Solid who set me up with some Cork, Bamboo and WoodFill from colorFabb.  I wasn’t sure how much I could push the pro with 3rd party filament, but it seemed that quality colorFabb was a good place to start.

The first filament I tried was the CorkFill from colorFabb.  I set it up at an extruder temperature of 210, a bed temperature of 55, and a 0.3 layer height.  I additionally used rubbing alcohol (instead of glue stick) on blue painters tape.  There was great adhesion and no problems what so ever.

The CorkFill not only smelled great (better than ABS), it printed very smoothly and looked just like chocolate.  While it is definitely not edible, it did prove to be a very nice texture that offered an interesting cross between what you would expect from a wood, PLA and ABS somewhat mixed together.  And while you think cork would mean flexible or flimsy it is anything but.  It may have little give but is in no way brittle.

PiGRRL Buttons

My only regret and downside of CorkFill was that I didn’t have enough to keep printing!  I was able to print some buttons for a PiGRRL 2  and half of a shave brush stand.  While my supply ran out, I certainly look forward to utilizing CorkFill for many future projects.

Half Finished Shave Stand

Half Complete Printed CorkFill Shave Stand

Next I tried printing the case for the PiGRRL 2 (portable video game system/ GameBoy clone) with the BambooFill.  After my quick read up on the material, since it was PLA based I used the same temperature setup as the cork.  I was just over an hour into the print and it happened…the BambooFill clogged the printer!  It was just short of a disaster.

Incomplete PiGrrl Case

Luckily over the course of a few days and XYZ Helpdesk tickets I received an answer…but not the one I had hoped for.  I prepared to use a torch and some acetone (separately) to clear the nozzle and get back to work.  However with all the hardwired parts I was advised in order to remove filament I would need to shove a large paperclip down the top of the nozzle repeatedly while using the load filament function at 200 (editors note:  Don't use a paperclip to try to clear a clog.  You'll probably just make it worse and might damage the inside of your nozzle.  Try a cold pull instead.).  Much to my dismay and frustration with their customer service, this surprisingly worked!  I re-calibrated the bed and loaded back in some ABS and got back to normal.  The calibration did wonders, even though it comes “pre-calibrated” you should make sure to utilize the calibration as it will really help the quality of your prints immensely.

It appears while the DaVinci 1.0 Pro can use 3rd party filaments, you definitely need to take your nozzle size into consideration and experiment with different heating and retracting issues.  This issue and my days spent trying to fix it put my cork and wood filament experiment to an end.  The cork was a win and certainly a filament I will be using again.  The bamboo I may even attempt again if I can get my hands on a larger nozzle or some specific heating example that worked for someone else.  The WoodFill however will not be tackled by myself or the DaVinci Pro.  If someone can prove it to work I would love to hear their feedback and process, but as for myself I will tread lightly with the bamboo and not push this budget machine further than I know it can go, especially when my maintenance time to fix it is very limited.

 

Kyle Mohr

KM Productions

 

Check out Kyle’s work at the below sites:

YouTube

Instagram

Facebook

In honor of the great month of October and the coming of Halloween, I thought I would share this little 3D Printing injury with you all.  

From my perspective, this is moderately amusing.  I've got decades of experience working in labs and around moving shop equipment.  I know where I'm at risk of a little scrape here and there and where I need to be more careful.  However, it occurs to me that people of all shapes and sizes, so I decided to do a little writeup around some of the dangers associated with consumer 3D printing.  You'll probably note that this extends to just about anything in a workshop environment.  This post will initially be populated by my wound picture and will get filled up with more as readers send me their stories of wounds from other categories.

Moderately graphic image coming up for the weak stomachs out there...

 

 

 

 

 

 

 

 

 

Danger - Sharp Edges

 

So, what happened?  This one is only very loosely a 3D printing injury.  I was in a mad rush to get something shipped and was reaching through spools of filament for samples.  My finger scraped against the edge of the inner bore of a spool that must have had a jagged section.  It was a sharp edge in a location that I wasn't really expecting.  

You'll find that your printer is probably has a few sharp edges.  One of our regular customers posts about concerns he's had with sharp sheet metal edges on his Flash Forge Creator Pro on the Facebook Flash Forge Users group page and what he's done about it.  Those glass plates that many of us use are great (have you ever removed a glass build plate and popped it in the freezer to remove your print?  Awesome), but it's a good idea to remember that they are sharp edges waiting to happen.

Another issue can be removing your print from the build plate.  A lot of the tools that work really well to help pry your print off the plate are sharp.  I really like using a cricut spatula.  The pallet knife, clamdigger knife and a sharp paint scraper are also popular.  They become dangerous because you're often putting a fair amount of force on it to get it underneath the part.  The part tends to just give and pop free, then the blade can come free to give you a nasty cut.  

The picture below is an aftermath of a friend's less than ideal thumb placement when she was trying to remove a stubborn print.  

One more place where you're going to encounter edges is support removal, especially of hard PLA supports.  The tools you will use to remove it and the material itself can be sharp enough to cut you.  Support structures are getting better all the time though.  Programs like Simplify3D and meshmixer provide you with easier to remove supports that might reduce the risk of cutting yourself like this.

Caution:  Hot Surfaces

Warning labels be damned!  I will not follow you!  They are there for a reason though.  The hot end is...

Wait for it....

Hot.  

Here is a mostly healed over blister from being too impatient to walk across the shop to grab tweezers to remove filament at the start of a print.  Nylon sure can hold some heat!

Splinters

I really hope someone sends in a pic because these are just nasty.  Have you ever removed support material or a skirt with your fingernail?  Me too.  It's a really bad idea.  I haven't been unfortunate enough to experience this for myself yet, but I've seen a few instances where people have gotten plastic splinters stuck under their finger nails.  It looks like it hurts a lot.  The pictures are terrible.  If you have one of these that you're willing to share, please message me!  

Just because PLA is used as a medical implant material doesn't mean you should test it out on yourself!

It's Electric

Alright, this is where I actually am (mostly) careful.   You've got a wide range of printers out there.  A very few are built to electrical safety standards, but things can go wrong.  When you are working with electrical devices, you've always got a risk of fire.  Google 3D Printing fire.  You will find some truly awful pictures.  People have lost their homes or worse.  Obviously, this is much more serious than the other things described above.  Please consider this when you're contemplating running a long unattended print.  At the very least, make sure you have fire alarms so that if the worst does happen, you or your loved ones will know when to leave.

 

 

 

 

Fall is an awesome time for 3D Printing.  There are many great events.  One of the biggest for makers and 3D Printing is the World Maker Faire in NYC.  

The 2015 event will be held at the New York Hall of Science on September 26th and 27th.  There will be a ton of amazing Makers showing off their work and lots of hands on activities.  More info about the Faire can be found here.  

Printed Solid will be there in the 3D Printing Village with some cool things to show off and some cool things to buy.  

Last year, we introduced our gumball machine filled with a bunch of random 3D Printed things.  The idea for this came out of necessity.   At a previous event, we printed 100s of little giveaway prints figuring that they would last easily through the whole event, but they were all gone within the first hour!  So, we ordered a gumball machine to slow the rate that the sample go out.  It was a big hit.  Kids loved it.  But we noticed that everyone who didn't get a robot was a little bit disappointed.  So, this year, we will have the machine loaded up completely with robots in a plethora of cool colors.  The robot of choice this year is a remix of Cerberus 333's 2013 Big Red design.  We call him Little Red.  If you follow us on twitter, then you'll know we've been running the heck out of this stl for the last few weeks.

The gumball machine will be stuffed with mixed color bots as well as a few special bots printed in bronzeFill, copperFill, brassFill, Stainless Steel PLA, and rusted magnetic Iron PLA.  We will also have some of the metal filled as well as solid cast metal bots available for purchase.  

Robots in assorted colors.  The guy in the center was made in bronzeFill, tumbled, and clear coated.

Robots in ProtoPasta Magnetic Iron that have been rusted overnight in salt water.

We will have 3 shelving units fully loaded with all types of filament and supplies from our shop available at discounted prices.  Last year, we had people asking for bags.  Seems like kind of an obvious thing for a retailer, but we didn't think to bring any.  So, this year, we had the foresight to order up some cool bags.  We'll be giving out these drawstring bags with purchases.  Or, if you're a reader of the blog, just ask and we'll give you one for free :)

 We will have some of our coolest prints featuring different materials that we sell.  Stained and sealed WoodFill Groot and Stainless Steel / BambooFill Thor's Hammer are two of my personal favorite's

 

In addition to showcasing prints in all of our favorite materials, we'll have a streaming presentation going through the whole show with some information on basic filament properties.  This should be very informative for those attending without engineering or materials degrees.  It will list out some basic properties of materials such as strength, flexibility, and electrical conductivity.  Each property will be given a brief explanation, some filaments that are good for that property will be listed, and a visual example of the property will be shown.  There will also be a handful of objects printed to show differences in properties for the different materials.  When I am back settled in from the show, I will be sharing this information on the blog as well.

Of course, what will a Maker Faire be if we're not actually making during the event!  This year, the Printrbot Metal Simple will be our working machine.  This printer has a super small foot print and is very reliable, so it makes a perfect printer for shows.  We'll have a few for sale at a discounted price if you want to take one home with you from the show.  

What will we be printing?  Well, we will definitely be printing with the new Proto-Pasta Coffee Filament for some of the time.  This is not yet available in our shop, but will be soon.  It gives off a slightly burnt coffee smell while printing (perfect if you like dark roast brews like Starbucks) and has a nice brown color.  It also offers a unique functional aspect.  The material can be post treated to create a higher temperature tolerance.  So, you get a filament that smells like coffee AND can be used in your hot car.  Sure beats having to smell nasty ABS!  Alex from Proto-Pasta will be stopping by at some point to present information on their materials and to give out samples.  

 Then we'll also be spending some time printing with Algae Filament.  

Product image and print by Walter Hsaio 
Bucky Ball (Fredbartels) / CC BY-SA 3.0

 

We'll also bring back the Garage Sale filament that we had at Midwest Reprap Fest 2015.  As a filament reseller, we order a lot of different things just to try.  Some make the cut.  Many don't.  Sometimes they don't make the cut because they are just terrible materials.  Those go in the trash.  However, a great many are OK enough, but just not quite up to our standards.  These are our garage sale filaments.  We'll have about 30-40 spools ranging from unopened 250g spools to opened with only a bit used 1kg spools.  We'll have these available for $5 each or 5 for $20.  If you're looking for a great deal, hit us up early.  These will not last long.  

Also...  Just in! 

We'll have some special guests.

Gordon LaPlante and Anna Lee, cofounders of Gcreate who make the awesome Gmax series of printers will be stopping by.  You might have also seen some of Gordon's awesome designs featured on thingiverse and 3dfilemarket.  They will bring some of these enormous prints with them to show off at our table!  All are printed in fabulous colorFabb PLA/PHA.

 

 

 

 

 

Introduction

This will be the first in what I hope to be a series of tips for optimizing your 3D printed part design for mechanical performance.  An apology in advance: I have a masters degree in mechanical engineering and 15+ years of industry experience.  I'm used to speaking to people in 'engineeringese' with all of the made up technical words that entails.  I am going to do my best to express things in layman's terms as much as possible.  One of the awesome things about 3D printing is that anyone can do it; you certainly don't need to be a mechanical engineer to run a 3D printer or to design parts to send to a bureau.  So, I'm going to try to structure this writeup in a way that anyone can understand it.  Inevitably, I'll end up throwing in some jargon without realizing it.  Please call me on it and I will revise.

 

Many times, people do not associate 3D Printed parts with strength, but this does not need to be the case.  Paying attention to a few fundamental design / mechanics of materials principles can greatly increase the strength of your printed part.  Combining these principles with advancements in available materials will allow you to produce parts that can meet the structural requirements of more and more demanding applications.

Stress Concentrations

In this first installment, we'll talk about stress concentrations.  When you put load on a part, the way that the load is distributed through the part is referred to as stress.  Materials are rated based on the amount of stress that they can carry.  The stress generated in the part is generally proportional to the cross sectional area of the part.  I think that as 3D Printer people, cross sectional area should be easy to understand; it is the area of the part when you slice it against the direction of loading.  Of course the stress exists in the full 3 dimensions, but thinking of the two dimensional space first is adequate to get the point here.  (Making things more complicated:  what exactly is a cross sectional area on something that has X perimeters and Y% infill?  We'll ignore that for now and pretend that the prints are solid since the concept still basically holds, but this makes things significantly more complex if we really try performing stress calculations.)
Think of a diving board.  The amount of stress in the board is higher with a large adult jumping on it than with a small child jumping on it.  Let's say that the board is rated to handle a 400lb person.  Now drill some holes in the board.  You will find that the load capacity is reduced and that it is reduced by more than the small percentage of material you have drilled out.  Now instead of drilling out a hole, cut two sharp notches in the side.  The capacity will be reduced even more significantly.  In both cases, the point of failure will move to the feature you've added.
This principle where the ability of an object to carry load is reduced by adding sharp features is due to stress concentrations.  Both the hole and the notches are called stress risers.  They change the way that the stress is distributed in a part and increase it dramatically at the location of the stress riser.  Any change in geometry is a stress concentration.

Removing Stress Risers

So what?  How can you take this knowledge and use it to improve your designs?
Three words for you.
Fillets, Fillets, Fillets.
Fillets are features that you add to the geometry to round out sharp corners.
Red piece on the right has a sharp corner. This is a stress riser. By smoothing out that sharp corner with a fillet as in the part on the left, strength will be more than doubled.
In many traditional manufacturing methods, fillets become necessary simply because features may be oriented in such a way that it is not practical to get a sharp tool in there.   Even when you can, sharp mill bits typically don't do better than about a 0.005" radius, so you naturally get fillets unless you pay $$ for more exotic manufacturing processes.
With 3D Printing, no such limitation exists.  You can make perfect sharp transitions that are terribly stress risers quite easily.
Here's another example.  I was at an event and another attendee showed me this part.  He said, "the design geometry suits our needs perfectly, but it keeps breaking."  To which I replied, 'oh, is it breaking right here?' and pointed to the sharp points at the ends of the semicircle.  At which point, as if on queue, the part in his hand actually broke at those points as he handed it to me.  The ends of the semicircles are pretty significant stress risers.
The corners of the D shaped cutouts present nasty stress risers. It doesn't help that the material around it is relatively thin. Expect sharp features like this to be a potential failure site and avoid if possible.
Now that we've learned about stress concentrations, what would you do to fix this part?  Fillets?  That could work.  You could move the flat surface back and add fillets.  You could also adopt a simpler solution and simply make the semi-circle into a full circle.  This may come across as a surprise to some.  Removing material will actually make the part stronger!  Yes, it will still be weakest at that point, but the amount of load it can carry will be significantly increased by removing that stress concentration.
I hope that this article will help you improve your 3D Printed designs.  Our next article will elaborate a little bit on how properties of the filament you print with affect stress concentrations (spoiler:  stress concentrations are much more significant in PLA than they are in Ninja Flex).
MRRF2015_1024Xx427   Better late than never, right? This year, I'm proud to report that Printed Solid will be a supporting vendor at the 2015 Midwest RepRap Festival.  This is an annual event held in NorthWestern Indiana where 3D printing people from around the world gather to discuss ideas and show off their work.  If you're into 3D Printing, hopefully RepRap needs no explanation, but just in case, here's a little primer. The Reprap movement is responsible for the existence of consumer 3D printing in its current state.  It embodies the spirit of open hardware and open software.  People from all around the world work together and on their own to use their skills to develop designs for printers and the supporting software, then freely and openly share those ideas to benefit the community as a whole.  It is nothing short of an absolutely awesome thing.  The name comes from the idea of a self replicating rapid prototype machine; a machine that could be used to produce parts to make a duplicate of itself.  You can find a lot more information at reprap.org. At the event, there will be people demonstrating their printers, speakers, vendors, and lots of cool conversation. I will be there with examples of prints in all of the great materials we carry as well as filament, hot ends, and displays available for purchase on Friday and Saturday only.  The material for purchase will be at a discounted price over what we sell on our site, but I can't guarantee what the selection will be. If there is something special that you want to buy, CONTACT US and we will make sure to bring it along prepped and ready for pickup. I will also have samples of colorFabb XT-CF20, colorFabb XT, colorFabb bronzefill (2.85mm only) AND brand new brassfill (only in 1.75 right now) available to give out, but there is a catch.  To earn your free sample, you will have to show us a cool print, so make sure to bring some along. Looking forward to meeting many of you!
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