A 3D Printing Workflow with Free Software

Solid Hollow Lattice

One of the challenges for designers (beginner and advanced) creating objects for 3D printing is finding software capable of doing the complex things we enjoy seeing in 3D printing news and exhibitions. There really doesn’t seem to be one program capable of doing it all, and this has been re-emphasised to me during my recent studies at MIT and a visit to Autodesk. However, there is some good news: if you’re able to quickly learn software, you can find an increasing number of freebies that seem to be specialising in small aspects of the workflow, which you can move between to create complex designs.

Form 2 Print Lattice

This tutorial will show you how I used completely free software to create a complex object during my time in the MIT course “Additive Manufacturing: From 3D Printing to the Factory Floor” as part of a group project, and is actually very quick once you become familiar with the programs. This particular design combines a hollow object with an internal lattice structure suitable for SLA printing on a printer like the Form 2 from Formlabs, which is what was used for the translucent version in the photo above. The white version in the background is a cross-section view of what is going on within the SLA print.

Step 1: The Overall Form

Clip 01 - 01

There are loads of free programs to use for creating 3D models – Tinkercad, Sketchup, Openscad, Sculptris, Fusion 360 (if you’re linked to an educational institution)… there are many more and you can certainly use your favourite. For this project, I actually used Onshape for the first time, which runs completely in the cloud (so no software downloading or limitations on computer operating systems/specifications). If you are at a school or university, you can get a free license. It works very similar to Solidworks or other high-end CAD packages, so if you are familiar with sketches and features, you will pick it up very quickly.

Basically, whichever CAD software you use, you want to create the overall shape of your object. In this case, I created an organic tear-drop shape using a “loft,” and cut a section out of the back so that it would clip onto a desk and act as a bag hook (part of the MIT design challenge).

Step 2: Make it Hollow

Many CAD programs will allow you to “shell” your design, making it hollow inside. However, if you can’t find the tool, or aren’t getting good results, we can do this in the next piece of software. But first, export your solid file as a STL (and if you managed to shell it in this step, export a STL of the hollow version as well and skip the rest of this step. You will still need a solid version for the lattice process).

Meshmixer Hollow

The next free program, which I think is a must for anyone with a 3D printer, is Meshmixer. It allows you to edit the normally un-editable STL file format, and I have previously written tutorials about how to do download files from Thingiverse and combine them in creative ways or add your name to a downloaded part.

If you weren’t able to hollow out your design previously, click on Edit>Hollow and set your wall thickness. Just like that, your solid object is now hollow, and can be exported as a STL.

A note for SLA printing:

Meshmixer Drainage Holes

When using the Form 2 3D printer for the first time, I was surprised to learn that the PreForm software doesn’t allow for the user to specify infill patterns in the same way that is commonly done with FDM printing. That is what created the need for this custom lattice infill, and this tutorial. So, being a liquid resin printer, the final important step is to add drainage holes so that the form doesn’t end up completely full of liquid, and errors don’t occur during printing.

Meshmixer again has this function built in. While in the Hollow tool, you will have the option to “Generate Holes” and manipulate their location. This is really important, as you won’t be able to do it again later once your hollow and lattice are combined (unless you’re familiar with the boolean commands in Meshmixer and manually add a cylinder from the Meshmixer menu to use as a cutting tool).

Step 3: Creating a Lattice

Lattices and 3D printing are best friends. But creating a lattice in many CAD programs is close to impossible, usually requiring advanced skills and a computer that can handle very large patterning features. nTopology Element is a free program that will dramatically simplify the process for you – simply load a STL file, choose a lattice pattern, and boom! your object is now a lattice. But let’s go through it a little more slowly.

1. Import your solid STL file into nTopology Element.

2. On the top menu, click Lattice>Generate

3. In the pop-up, you can play with the lattice patterns (called “Rules”), the size of each lattice volume, and click Generate to get a preview. When you’re happy with the result, click on Apply.

nTopology Lattice Trim

4. You will notice that the result has the lattice coming outside of the original object. This is because only whole lattice volumes are used to fill the object, rather than automatically being trimmed to fit. So we must do this manually. In the top Edit menu, click on the Trim tool. A new pop-up will appear, asking you to select the Lattice geometry and the Trim Volume (original model), which you can select from the drop-down menu on the left. Click apply and the lattice will be trimmed to fit perfectly within your original design.

5. At this point, the lattice is made up of vectors – they have no volume. So the next step is to use the Thicken tool on the top menu to provide a diameter to your lattice.

nTopology Tutorial

6. Lastly, the thickened lattice needs to be turned into a single mesh that can be 3D printed. The Mesh button (where it says Interchange on the top menu) will join everything together and give you a single mesh. In the drop-down menu on the left, you can now right-click on the mesh, and click on export to get your STL file.

Step 4: Bringing it all Together

The free version of nTopology won’t let you stitch multiple files together, however the Pro version will if you ever end up with the need for a full license. So back to Meshmixer to bring it all together ready for 3D printing.

1. Import the hollow STL and lattice STL into Meshmixer (when you click on import for the second file, use the Append option).

2. You will notice that the ends of the lattice stick out from your object. There are 2 ways to correct this: Option 1 is to use the sculpt tool with the “Flatten” brush to go around and push the ends of the lattice inside of the object boundary – it’s just like pushing clay.

Meshmixer Sculpt Lattice

Option 2 is to ever so slightly reduce the scale of your lattice. With the lattice selected in the pop-up Object Browser window (on the right of my window), click on Edit>Transform and you can either manually manipulate the scale, or more accurately type in the reduction in the transform window (with the uniform scaling option ticked). You should only need a small reduction until the lattice fits just inside the outer skin of your object.

3. By turning off the hollow part in the Object Browser, but keeping it selected, you will get an X-Ray view into your object to check if the lattice and hollow part are intersecting. This can help with any final alignment. Remember; you want the lattice touching the solid shell, but not poking through so it’s visible, or loosely floating within the hollow.

Meshmixer Lattice View

4. In the Object Browser, [shift]+click to select both parts at the same time. A new window will appear that will allow you to Boolean Union or Combine both parts together, creating a single object.

5. Export the final STL and you are ready for 3D printing.

SLA Form 2 Print Fresh

Step 5: Getting Creative

Meshmixer Creative Lattice

Once you get a bit of experience with this process and some of the other tools in Meshmixer, your imagination is the limit! You can really begin to play with different combinations of solid and lattice structures depending on the result you want. Have some fun and feel free to share any of your own creations in the comments section.

– Posted by James Novak

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The Meshmixer Mashup: Mashup-Rex!

Tutorial Meshmixer Mashup

The mashup is a favourite technique in the music world that combines two or more songs together into a single song. They might be from completely different eras or genres and when cleverly mashed together, they create a new smash hit. But did you know that creating a 3D printable mashup is just as easy as creating a musical one? Take a bit of File A, mix it with File B, and you now have your own creative design.

Over the last few weeks I’ve been putting together a new tutorial for my friends at Pinshape, which includes my first video tutorial as well as the usual step-by-step process to follow along with. Click here to learn how to mashup STL files in only 10 easy steps using the freely available software Autodesk Meshmixer.

The mashup is often called a Remix in the 3D printing world, and is a great way to build upon other designs and add your own creative touch, or re-purpose a design for a new application. The video tutorial is a real-time look at the process, which with a bit of practice, will have you remixing new designs in a matter of minutes. If you want to follow along, you just need to install Meshmixer on your computer, and download the 2 T-Rex files used in this tutorial which are free on Pinshape:

  1. Low Poly T-Rex by steven_dakh
  2. The T-Rex Skull by harry (we are only using the head piece, not the jaw)

Mashup-Rex

Alongside the tutorial is my latest design, the Mashup-Rex. I have made this available for free on Pinshape, just click here to download the file. Maybe you you will create your own remix of my remix? If you do, or you just 3D print the Mashup-Rex for yourself, please share it on Pinshape to add to the community and see how far the design can go! In the version pictured above I simply used a coffee stain to “age” the skull, similar to my previous print of the Star Wars Deathtrooper. I’m enjoying this simple technique at the moment, although you may like to use a 2-tone print, or go all out with some painted effects.

Happy mixing!

– Posted by James Novak

Is That A Clogged Nozzle, or…

20170413_3D Nozzle Clog

No it’s just a clogged 3D printer nozzle, thanks for asking!

2017 seems to be my year for repairs on the Cocoon Create 3D printer, it was only a few months ago I wrote a big post about repairing and replacing the PTFE tube after it got seriously clogged. I did some research and found out exactly what the tube is for, and bought a roll of spare tube for future repairs (click here to read more).

Lucky I did! This seems to be the same sort of problem, however instead of the PTFE tube just getting clogged, when I opened up the nozzle the tube had become melted and broke off inside, completely stuck as you can see in the photo. I wonder if the spare PTFE tube I had installed was made from dodgy materials, allowing it to melt? Or maybe the ABS filament had just found a way around the outside of the tube and caused it to clog. Either way it’s getting a bit frustrating to have the same issue.

Luckily this wasn’t too difficult to fix (although I did jump straight on Ebay and buy a couple of spare brass nozzles – just search for RepRap MK10 0.4mm nozzle since the Cocoon Create is based on the RepRap Prusa i3). Using a drill and holding the nozzle with some pliers, I gradually worked my way up from a 2mm to 4mm diameter, clearing out the clogged material. 4mm is almost exactly the same as the internal nozzle diameter, so it cleared everything out nicely.

With some new PTFE tube installed, I’m back up and running again and the first print is coming out nicely (stay tuned to see what it is). Let’s see how long it lasts this time…

– Posted by James Novak

From Sketch to 3D Print

Sketch to 3D Print

Designing your own 3D printable object can be daunting if you’ve never used a 3D CAD program before. This is a challenge that one of my university classes is facing, with most of the students new to 3D design, but eager to begin experimenting with 3D printing. So this week we explored a workflow that allows them to take their hand-drawn sketches through a couple of simple processes, resulting in a 3D printable file, without having to model in 3D from scratch. So here it is just for you – follow along and let me know how you go.

Step 1: The Sketch

biro sketches

This is the easy part! Find a sketch that you’d like to turn 3D. It’s best if it’s drawn clearly in pen, so if your sketches are in pencil just trace over them on a fresh sheet of paper. For this example I’m borrowing a sketch from online. You must then digitise your sketch – best using a flatbed scanner, or take a photo in good lighting conditions so you get good contrast between your linework and paper.

Step 2: Vectorising

Illustrator Tracing

We are going to use Adobe Illustrator to automatically trace the outlines of our sketch. Place your sketch into a new document, and you will see a “Live Trace” or “Image Trace” button appear (depending on your version of Illustrator) near the top menu. You may find that one of the preset options will give you an accurate tracing, or you will need to get into the options and start tweaking the settings. I have an older version of Illustrator, but the settings that work for me are shown above. What you are looking to achieve is a good level of detail, and nice closed lines. Once you have a good result, you can use the “Expand” button to turn the result into individual lines that can be selected. You can also go to the menu and select Object>Ungroup so that your linework is no longer all grouped together as a single item.

Step 3: Exporting

Illustrator SVG

If you have a collection of sketches like this example, you will want to now Save your file (so you can come back to it and make changes later on), and then delete everything from the file that you don’t want to turn 3D. For this example, I have just left the flower tracing that was in the top-right corner. Go to File>Save As and save this drawing as a SVG file. This is a 2D drawing format that will be recognised by our 3D software.

Step 4: Going 3D

For this example we are going to use the freely available 3D software Tinkercad – one of the best features being that it runs from your internet browser, no need to download and install anything. I recommend it as a great place to start your 3D modelling journey, however if you’re already using a more advanced 3D CAD program you can still follow along with this tutorial – the process will be quite similar.

Tinkercad Import SVG

Create a new Tinkercad file, and at the top right of the workspace is the “Import” button – select your SVG file and it will automatically be turned into a 3D object as shown above. Depending on your sketch and requirements, this might be all you need to do and you can jump straight ahead to Step 7: Exporting. However I want to make some modifications to this design now that I have a good starting point in 3D.

Step 5: Modification

Tinkercad Cut

For my needs this object is too thick – I only want it to be 2mm tall. In the right panel of objects is a translucent box – this box is like a cutting tool, anywhere it touches my 3D object it can be used to cut away at it. Place a box in the middle of your 3D model, and use the Length and Width sliders to fully enclose your 3D model. Lastly, rotate your model to a side view and you will see an arrow pointing up or down – click-and-drag on this to move the box up 2mm above the workplane.

Now select both the 3D model and the box (either click-and-drag a selection box around the workplane or hold the Shift button and select both objects) and you will notice at the top right the Group icon becomes available. Click on this and Tinkercad will subtract the box from the 3D model, leaving just a 2mm thick object.

Step 6: Patterning

Tinkercad Pattern Duplicate

Rather than just printing one of this design, I want to create a more complex pattern. Firstly I need to scale the design down so that it’s a bit smaller. Do this by clicking on the object, holding the Shift button and using the corner handles to click-and-drag the object down in size – mine is about 40x40mm.

With my object selected, at the top left of the window are the standard Copy and Paste actions, as well as the Duplicate option – this is the option I use to make copies. It may copy the object in the exact same position as the original, so when you click Duplicate just click-and-drag this copy out into a new position. Repeat as many times as you like to create a pattern.

When you’re happy with the design, you will need to join all of these individual elements together into a single object. Similar to step 5, select all the objects together and the Group button will become active – however because all of these objects are solids, the Group function will join them together rather than cutting away.

Step 7: Exporting

When your design is complete, use the Export function at the top right of the window to download the object to your computer. The STL option is most likely what you will want for 3D printing. The STL format is the standard file type for all 3D printers.

Step 8: 3D Printing

Up Plus 2 Pattern

Finally you can load your STL into your 3D printing or slicing software and 3D print! If the print doesn’t give you the result you want you can either go back to the Tinkercad file and make some more modifications in 3D, or take a step further back to Illustrator and modify the original linework.

The process is not perfect or overly accurate, however for designs like fashion or simple experiments, this can be a good workflow to try if you’re better/faster at drawing by hand than modelling directly in 3D software. If anyone has some different workflows they enjoy using, please feel free to share them in the comments section 🙂

– Posted by James Novak

New Year 3D Printer Repairs

20161223_prusia_i3_nozzle_jam

After something like 150 hours of 3D printing leading up to Christmas it’s no wonder that my Cocoon Create decided to extend its holiday with some down time to kick off 2017. There have been 2 problems to do with extrusion that I’ve come across, and thought they might be handy to know how to fix for others with this printer, or indeed any of the many derivatives of the original RepRep Prusa i3 which this printer is based off.

The top image shows the first problem which I noticed after some jamming and issues swapping out filaments – basically a build-up of filament “powder” over time from the gear grinding it when it’s been jammed. This one’s a nice easy fix, just a cleanup and a reminder to open up the extruder occasionally to keep things clean. If you’ve never opened the extruder before it’s nothing scary, just 2 bolts on the left where the fan is mounted to the heat-sink which opens the whole thing up as shown above. You might be surprised how simple the whole mechanism is.

20170108_prusa_i3_ptfe_tube

After fixing this problem and doing a couple of prints, I then noticed the filament was getting jammed again and I couldn’t push filament through the nozzle no matter what I did. Opening the extruder (same process as before except now removing the small screw on the right of the metal block to release the actual nozzle) the problem was pretty clear – a clog in the PTFE tube which you can see above. A lot of people are surprised to open their extruder and find a plastic tube inside, and this is the first time I’ve really had a problem with it. This tube is made from PTFE, basically Teflon like in your non-stick frypan, and seems to serve a couple of functions from what I’ve read online:

  1. it stops heat from the nozzle climbing too high into the extruder and prematurely melting the filament, which would cause serious clogs.
  2. being non-stick, it helps the filament keep sliding smoothly down to the nozzle without sticking as it gets warm.

A very cheap, simple part that has a lot of responsibility. Mine must’ve gotten worn out or slightly dislodged during my last attempt at fixing the extruder. Thankfully my printer came with 1 replacement, which I cut to size (make sure both ends are nice and square so that there are no gaps for filament to get caught in) and now I’m up and printing again with no problems. Also I’ve jumped onto Ebay and ordered a 2m length of PTFE tube (inside diameter 2mm, outside diameter 4mm) from China for $2.50 – I recommend anyone who has a 3D printer with this part order some PTFE tube as backup, it’s very cheap but if you need to buy something locally in a 3D printing emergency, prices look at least 10 times higher. For a couple of dollars it might just help keep you sane.

Some good forums discussing PTFE tube issues:

I’ve previously written about another type of clog where filament breaks off inside the extrusion tube as you’re retracting it, and you can’t force a new piece in – check out the post here if this sounds like what you’re experiencing.

Happy 3D printing, happy new year.

– Posted by James Novak

Repairing 3D Prints with a 3D Pen

20161216_3doodler-repair

It’s been a while since I last played with my 3Doodler Pen to repair a broken 3D print – the results were pretty cool, although it takes some practice to get reasonable results. Check out the post and images here. Some people make pretty amazing sculptures with the pen, however I find the real value in using the pen to fill gaps created by warped 3D prints and fix other cosmetic problems.

One of my latest projects is assembled from 16 separate pieces printed on my Cocoon Create 3D printer (60 hours worth of printing!), and inevitably with such large pieces printed using desktop FDM technology, there are some gaps caused by print warping. Most of them are reasonably small, but some like the ones shown above and below are quite large. Unfortunately the 3Doodler uses 3mm filament, meaning that I couldn’t use the same 1.75mm filament used to print the parts to begin with, but given that this project doesn’t need to be cosmetically pretty (prototype only), a different shade of yellow that came in the box will do.

20161214_3doodler-repair

The first step is of course to use the pen to extrude material into the cavity, ensuring to move slowly and use the hot nozzle to bond the new plastic with the original. It can get a bit messy and smelly (do it in a well ventilated area – I had a fan blowing to keep a lot of the fumes moving away, but there were times my eyes were stinging), and as shown in image 2 above, might look a bit rough, but that’s OK. You can go back over some of the rough patches using the side of the hot nozzle to try and smooth them out, not extruding any material but using the nozzle like a hot rolling pin. This technique is also great for blending some of the sharp edges or smaller gaps that don’t really need to be filled. The final step is to use a metal file to clean things up, giving a much smoother finish.

Admittedly this process wasn’t all smooth sailing, my 3Doodler kept getting clogged despite me taking it apart and cleaning it out – I have a feeling it might be the material quality and/or the temperature of the nozzle not being quite as hot as it needs to be, so a lot of time was wasted trying to manually push the filament through the pen and get a steady flow. I did notice that when I pushed the hot nozzle into my original print (the darker yellow plastic) it melted much quicker than the 3Doodler filament, despite them both being ABS. So material quality is likely the cause. But the final result is worth the pain, gaps are cleaned up nicely and the surface is nice and smooth. Time for some testing!

– Posted by James Novak

When Layer Orientation Matters

20160819_Meshmixer Plane Cut

Often when you are 3D printing the main thing you think about is how much support material your print will have, and you orient your print to minimise this – reducing material waste, print time and any manual post-processing to clean up the print. However sometimes the best print orientation for these reasons is not the best for mechanical strength, and I’ve just discovered this with one of the parts for the InMoov robotic arm I’m currently building (see the first collection of 3D prints in my previous post).

The “RobServoBedV6” part is where the 5 servo’s connect that control the individual finger movements, using screws to fix them in place. However some of the stands are splitting as I screw into them as shown in the photo above due to the layer orientation. Yes I could use super glue to fix them, but the split will just happen  somewhere else. So I’m going to completely cut the stands away from the part, and re-print just these stands in a different orientation to improve their strength. This is where the free program Meshmixer comes in very handy, and I’ve previously published a few examples of how to use it for my friends at Pinshape – just click here to find out more.

In the top right image you can see the first step of using Meshmixer to edit the STL file. I have used the Plane Cut tool to slice away the bottom plate, and then repeat the process to remove the other 2 segments which seem to be strong enough for the screws at the moment. This leaves me with the 2 stands that I’m having issues with. These can now be exported as STL’s ready to 3D print (orientation is not important here, this will be set in my 3D print software).

Cura from Meshmixer

I’m printing these parts as we speak on my Cocoon Create 3D printer, and have used Cura to prepare the parts and get the G-code. As you can see to the left, I have oriented the parts so that the layers are perpendicular to the original orientation, meaning that when I screw into them, the force from the screw will not pull the layers apart. Super glue will hold these replacements onto the original part really well as they are printed in ABS.

If you are designing your own parts from scratch in CAD and intend to screw directly into them, keep this issue in mind. However if you’re downloading a STL where modification isn’t as easy, knowing this simple trick in Meshmixer can really help you repair and improve a part rather than trying to re-print it from scratch and potentially use a lot of support material in a different orientation.

– Posted by James Novak

Design a 3D Printed Snap-Fit Enclosure

20160623_Pine64 Enclosure

Today I’m pleased to share a tutorial that I’ve written for my new friends at Formlabs called “How to Design 3D Printed Snap Fit Enclosures.” Follow the link to read all the details, but in short, this tutorial will guide you through some of the important steps to designing your own custom enclosure suitable for 3D printing, and featuring a snap-fit detail so that you can easily open and close the enclosure without needing any tools. The tutorial is done using Solidworks, however you should be able to follow along no matter which 3D CAD software you use, even the free ones like 123D Design – the process and tips are exactly the same.

For this tutorial I used a PINE64, the famous $15 64bit computer funded on Kickstarter in 2015. The enclosure is designed to offer something unique and exciting to complement the computer, and of course take advantage of 3D printing. You can access all of the ports and features with the enclosure fitted, and there’s a great spot on top to store SD cards, USB sticks etc.

By the way, if you just want the enclosure without following the tutorial, of course I’ve uploaded the design to Pinshape, Thingiverse and Cults so you can download it and print it for yourself!

– Posted by James Novak

Brimming with Success

20160712_3D Print Brim

Excuse the headline pun, but this post is all about 3D printing using a brim, which evidently can really improve your success rate with large flat surfaces.

For those not familiar with a brim, it’s an option in some 3D print software (such as Cura) that lays down an extra width of material around your object and attached to it, one or two layers tall. You can see the brim around my enclosure in the top left image. Essentially this extra material creates a stronger bond to the build plate, helping to fight the contracting forces of the cooling plastic that can commonly cause warping. Of course there are many other ways to combat this, including laying down some glue or adhesive spray, printing the part in a different orientation, or using an enclosure to keep the print warmer so there is less warping from rapidly cooling plastic. However these aren’t always an option, so using a brim can be a really effective solution that only wastes a very small amount of extra material.

In the top right image you can see my first attempt at printing this enclosure half, which is very clearly warped as the outer edges lifted up from the plate under the contracting forces of the cooling plastic. Support material was used, but nothing else. In contrast, you can see the middle image which is the end result once the brim from the left image was removed – perfectly horizontal! This is really important for this design since it is one half of an enclosure, and the warped version simply won’t fit properly with the other half.

20160712 CuraIt’s certainly not something needed for every print, but for large surfaces it’s proving to be very successful. If you’ve had similar problems with warping and haven’t tried a brim yet, it’s worth giving a go – you can see where to access this setting if you are using Cura on the left, very easy, or if you are using another program to slice and print, have a look through your settings. The raft is another option you may have used, however the raft builds up a lot more material underneath your entire object which is wasted. It can also be a good option though, especially if you are using a printer like the Up Plus 2 which does not have the option of printing a brim but will do a good job with a raft.

– Posted by James Novak