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Making: The Simple XL

We never really thought far enough ahead when building the Simple XL, to think that others would want to transform their Simple into an XL version. After getting quite a few emails asking how we did it,  I decided to start to put together some information on how it was done. Typically for things like this I would finish the entire post before putting it out there on the web but, I have had an many people want whatever information we have to offer on the XL. So this will be a work in progress.

Parts required for the transformation from Simple to XL:

• 8mm rods – Depending on the overall size you want to end up with will deturmine the length. (We were able to re-use some rods from the stock Simple.)

• 5/16ths threaded rod or ACME rod – Either one will work but, you will need at least 14″ of it. (Consider some of that will be used up by how it’s mounted)

• All the wood pieces for the XL – We used 5.2mm solid birch wood. You could potentially use almost any material between 5-6mm thick. These can be scaled up from the stock Simple files to a size of your liking. (Remember some pieces will have to be adapted to fit correctly.)

• Some Acrylic or Lexan – This is not a requirement but, Lexan works great as a print surface for PLA and is used to mount the Printrboard to.

• Spectra line – We were able to re-use the Spectra line from our original Simple. We are also working on a version that will use GT2 belts and pulleys. (Depending on how you cut the line for your original deturmines if you will need to get more or not.)

• Misc Cable Wrap – We used several different kinds on the Simple XL but, ultimately it is up to you on what kind of cable wrap is used.

• Fan For Extruder & Prints – This also comes down to preference. We used one to cool the extruder gears and filament before it enters the hotend as well as another for cooling prints.

• Large Zip Ties – We used standard 8″ ones and also considered using metal strap zip ties but, we eventually deturmined that metal ones would be overkill and were not required.

• Misc Nuts & Bolts – Some of the ones from the stock Simple we were able to re-use but, a large portion of new ones are needed for primarily the main structure.

• Washers – We used several different sizes and assortment packs of washers are easy to find. (In many locations on the printer washers are not required but, we used them on the main structure as we found that they help to distribute the load more evenly.)

• Wiring – More wiring will more than likely be needed especially if you decide to run your wiring along the bridge as we did. (Running the wiring along the bridge is recommended because it puts less strain on your wiring making last longer. This method also keeps all required wiring nice and neat for easier troubleshooting.)

• Stand-Offs – 4 were required for mounting our Printrboard and can be made instead of purchased.

• Aluminum tubing – This piece is used to help stabilize the smooth rods on the X-axis and is not required. (You can use plastic tubing or several other types and shapes.)

So far that’s all that’s needed for the upgrade from the Simple to the XL and a lot of what’s listed is optional. The most difficult part of the build was figuring out what parts needed to be scaled up and what needed to stay the same. Primarily the parts that need to stay the same are the holes for mounting your motors and things of that nature. If we can be of any help or you are interested in stepping up your Simple’s size to something a little more extra large, feel free to post a comment or get a hold of us via email or twitter. We will continue to update this, “Making of The Simple XL” as we go.





Posted from RepRap Squad HQ


RepRap Squad’s Simple XL


We wanted to find a way to say thanks to the Printrbot team as well as Brook for instilling inspiration and the want to, “Make in America.”

RepRap Squad has been working very hard to finish up the Simple XL. The XL is a scaled up Printrbot Simple with a few modifications. Its z-axis comes in at a huge 12″ with the stabilizer bar (14″+ without) , the y-axis has 8″ of reach and the x-axis is 11″. So that makes a realistic size of 12X8X11 or 308mm by 203mm by 279mm. Making the XL outrun the recently retired LC for print space as well as the new enlarged Jr. V2. We came up with this idea a while back because we love the Simple but, it just seemed a little too small for our over the top taste. We also wanted to create something cool to show Printrbot that they inspire us everyday to, “make in America.” The Simple XL can actually print the size of an assembled original Printrbot Simple with space to spare. This throws the Simple platform in the ring with much larger more expensive printers.

The Concept: “If you make it bigger, they will come.”
The idea itself seemed simple enough, ” make a bigger, more extreme Simple. One that could out print its older brothers.” It wasn’t until we really got into adapting the design, that we found out it would be as challenging as it turned out to be. Getting everything to scale was important because who wants to see a giant Simple with an itty bitty direct drive extruder? Not me, it was a constant battle between figuring out what needed to be enlarged and making the parts that couldn’t be enlarged look correct. Another issue we had was the bearing mounts on each axis.  Surely if we mounted them the same way as the original simple was, we would have some seriously sagging axis’s. The solution to that problem was to space them out a bit. We knew from the start that the small 4″ zip ties wouldn’t cut it, so we went straight for the largest ones that would fit. These zip ties are significantly stronger and hold everything in place with minimal stretch. We originally debated using metal zip straps but, after extensive testing with these larger zip ties we realized that these are the correct ones for this build.

We made a few small changed to the design and one of them being the bed. We built it so it can be adapted to use Printrbots new aluminum bearing blocks. This was made by lower our print platform to accommodate for the size of the bearing blocks. We also made a solid birch bed as well as a thick lexan bed as we’ve found that lexan works excellent for printing PLA. Eventually we will add a thick aluminum plate for the printbed on the Simple XL as well as a heated bed for printing ABS and other filaments. Another part that we felt was essential was a fan for the direct drive extruder. This keeps the filament cool as its being pulled through the extruder which helps with binding issues. We mounted the fan to the extruder using custom builts stand-offs. It was a little tricky to mount the stand-offs as we had to make sure each layer of the extruder was flush. We accomplished this by milling out little pockets for the bolt heads.

Making Modifications Where Needed
RepRap Squad wanted to keep this build as true to the design of Printrbot’s Simple as we could, so we only made a few modifications that we felt were important for reliability and print quality. Most of these modifications are standard running gear for current Simple owners. Besides size we added the fan on the direct drive extruder as mentioned earlier. We also re-routed the wiring so it followed the bridge and went through the rear. This required more wiring needed but, kept all the wiring organized and out of the way. It was well worth the time and effort. Another change over the original design was the spacing of the 8mm bearings. Spacing them out gaves us much more stability as well as left room for an upgrade we will be testing out later using Printrbot’s aluminum bearing blocks.

So far we are even more excited with the build then we were originally. The XL proved to be stronger and more accurate than originally anticipated. We have a huge line-up of modifications to test out with a future iteration named the Simple XL V2. One of those modifications will include a bowden extruder option. Another mod will include the aluminum bearing blocks and a new heated bed complete with a thick aluminum printing plate. The V2 Simple XL will have lots of new technology as well. A plan is in the works for a dual extruder setup as well. We have also started designing the, “tower” add-on that Printrbot recently released for the original Simple. More then likely the spool mount in the original design will be adapted to a use for the future dual extruder XL. This build will be referred to as the, “Simple 2XL” for easier referencing. You get the idea, the Xl with the tower mod and dual extruders will be referred to as the, “Simple 2XLT.”

We would like to give a special thanks to all the people at Printrbot as well as John Davis AKA ei8htohms. John D. has helped keep this build on track and gave his personal time to help. He consulted with us on this build back from when it was an idea, all the way until now. (ei8htohms) has his own site and its definitely worth checking out as he has all kinds of good 3d printer related stuff.

Here are the pics that we’ve all been waiting to see. I present to you, RepRap Squad’s, “Simple XL.”


We are amaized every time we look at the Simple XL, it turned out better than we ever could have expected.


The Simple XL, its definitely not your ordinary Simple.


Video's coming soon, we used the Printrbot Plus firmware with a few add-ons of our own.


We decided to re-route the wiring along the arm of the XL which required a little extra wiring but, we found it was well worth it in the end.


The optional lexan bed gives us superior grab when we lay down our PLA filament.


The original Simple finally has someone to look up to, literally.


Here you can see the size of the original Simple that was milled on our CNC VS the Simple XL


We will be eventually making several iterations of the XL including a Tower Add-on as well as a dual extruder setup.


Printrbot always says, "make in America" and thats just what we did.


There is enough print space to print a complete Simple original


We wanted to throw a little of our own flavor in the ring, so we added a dual lexan mount for the printrboard


Cable management was a breeze with the use of several different kinds of cable sheathing. We also printed out a coupler from the original printrbot to pay homage to the bot that started it all.


We wanted to keep the design as close to the original Simple as much as possible but, we found a new technique using a pully that worked great with the added weight.


We can't wait to start designing all the add-ons and modifications that will soon be tested out on the Simple XL


Update: September 14th 2013
With all the positive attention we’ve received quickly after releasing the XL we knew that we had to get started on taking the Simple XL to the next level. We are currently working on a lexan mount for the power supply which will keep everything even more portable than before. We wanted the XL to not just be another large format printer. We wanted it to be a large format printer that would be ultra portable. We will be working on making it as portable as we possible can while still bringing you great future modifications like a dual extruder setup and the tower add-on similar to the one Printrbot just released. Only in a more XL size. A lot of really neat innovations will be coming out of this build in the way of add-ons, modifications and insight into the world of the original Simple. The one that started it all, Printrbot’s Simple.

Update: September 16th 2013
After our meet at Makers Faire PDX we came up with a lot of neat ideas. We were caught off guard at Makers Faire when asked for a business card and the maker yelled out, “you’re the guys who built the Simple XL!” I replied back to him with a simple, “yes.” I was quite amazed that someone knew my work. Especially something that had been released a few days ago. After chatting with a bunch of different people within the local 3D print community. We came up with a few things that were of interest as far as add-ons and modifications for the Simple XL. Originally we had planned on building a scaled up version of the “Tower” add-on that Printrbot recently released. After thinking about the uses, it has taken a back seat as of now. The reason we decided to shelf that add-on was because the main upgrade with the tower mod is stability. Stability and strength was one thing the XL had already overcome by its size, materials and slight design changes. The other up side to the tower add on was the spool holder. We could easily come up with another design that would go along with the simple design with form following function.

One idea that was brought up by multiple makers was power switch, reset, disable motors and status LEDs. Now we just need to figure out a way to integrate those into the XL’s platform. For LEDs it seemed the most important uses that are wanted consist of: Hotend ON, ready to print, Error, power and endstop reached for each axis. We already have end stop LEDs that are integrated into each axis’s endstop. The only problem is the fact that you can’t see the majority of the LEDs due to their mounting locations. We will take all these wants into consideration. Using the ones that make the most amount of sense without creating a huge panel of switches and LED lights. Today we will start to map out this portion and hopefully have at least a mockup of this to test out its viability.

We came up with quite a few different ideas for a mount for the laptop PSU. We had a few wants when we started brainstorming. It needed to be able to be mounted on the side of the Simple XL as well as have the ability to be detached for a desktop stand option. We created a few crude prototypes, starting with cardboard and working our way up to a full scale prototype. After a bunch of failures we came up with an option that fit our requirements and offered an appealing look. We took a few pics so you could see basically what we came up with. There will definitely be a lot more development before a design is finalized.


Here's one of the prototypes we came up with. It clicks onto the side of the Simple XL & locks into place. It can then be removed and used as a desktop stand.

Update: September 18th 2013
Today we started out early working on a switch and status LED panel. We came up with a small 2 switch, each with active LEDs and a 3 status light system that was small. We built a prototype for it and we are currently mocking up different mounting locations. The location we found most viable was at the rear of the Simple XL. We made up some custom mounts for the two switches and then mounted those on lexan. We used a thinner piece of lexan that was bent using a brake to give it an angled mount that was both convenient and asthetically appealing. Today we will finish mounting both the switch/status panel and the mounts for the detachable PSU mount. We should be able to get a few pics of these prototypes up for you to check out.


You can see that we are trying out different mounting locations and different types of switch/status LED locations.


You can see the floating mount a little better. This mount was primarily designed with mobility in mind.

We decided to see what you think the next mod or add-on should be. Either share by posting a comment or via email at:
Let us know what you would like to see as an add-on or modification and have a chance to win that modification custom built to fit your Simple or other RepRap.

Update: September 19th 2013
Today has been full of a lot of different tests. We made a full scale mock-up of the switch/status LED panel and mounted it. There has also been extensive testing with insulation materials for our new heated bed that we will soon be adding. We found a material that is semi-clear and ribbed that so far has tested extremely well. We will release more information on this later on after final testing has been completed. Anothet test that worked a lot better than we anticipated was the intake duct for the extruder fan. It seemed to smooth out a few small issues we had periodically with binding filament. The fan worked well without the duct on shorter jobs but, we found out that it needed something to help keep it cooler during long term operation. So far after several 5-6+ hr prints results look promising. We will continue to test this duct out and make modifications were needed.

Another small issue we noticed was a little bit of backlash within the z-axis. So we started to come up with a solution employing techniques we used within our CNC machine builds. Using a spring under tension with a brass nut helped to almost eliminate the backlash we have seen. It still needs a little more work before we settle on a final solution. We will post more results on our test findings as soon as they are concluded.


This is one of the switch/status panel prototypes. We still haven't decided if this will be used or modified. This is just the mock-up.


Now that we have gone through calibration, we are experimenting with different setups. One of them includes this intake duct to cool the extruder gears and filament.


If you notice on the print bed you will see ribbing. We're testing out this new material for our heated bed. Early tests look promising.


This location has been selected for the top two best places to mount the status panel as it is out of the way but still accessible when needed.



The switches/status LEDs we used for this was: blue LED for all system on, orange LED for end stop trigger, blue LED for hot at temp. One of the two switches is to turn on/off all power and the other is motor cutoff. Each switch has an LED to let you know wether it is active or not.

Update: September 23rd 2013
Now we are currently working on a handheld setup that will allow you to have complete control of your printer. The options we are including in this setup are: Real-time checking on all available status’s of your printer, manual jog control, feed control, adjustments on the fly, print from SD and many other important options. We are in the midst of perfecting this setup for our Simple XL but, it will be available from us to be used on almost any bot on the market. More information on this will be posted when all testing is finished.

Main Features:
• Color TFT Screen
• Standalone operating system
• Print completely without the use of your computer or laptop
• Have complete control of your printer
• Touch screen control as well as some programmable buttons for quick options
• Ultra portable and light
• We are aiming for the sub $100 dollar range to keep it competitive with regular LCD\SD options even though it does much more

Today we are attempting to finish up all the hardware on the touch screen control. The first prototype has already been finished and is operational. We are now trying to find ways to get the cost down for our production version. So far we have determined that Bluetooth seems to work more effeciantly than WiFi in short range tests with the current configuration. More then likely it will be up to the user to determine which is preferred as both are planned to be included. We are also diving into an IP camera option. That way you can view your bot anywhere your WiFi is available. It is looking like the a version should be ready for the first few beta testers within the next month or so. More then likely we will release 5 beta’s out into the world, update and reconfigure if needed with the production release following soon after.

Beta Release
What kind of testers we’re looking for:

•Must have background in software and hardware integration
• A natural problem solver who isn’t afraid of troubleshooting potential issues that may come up
• Preferably an owner of at least 2 or more 3D printers that are of different types. (We want to be able to test this on as many different platforms as possible)
• Someone who is good at documenting their experience with the product and is willing to give regular feedback via email.
• Preferably someone within the U.S. but this is not a requirement and will be taken on a case by case determination. (This is due to time it takes to ship and clear custom’s)

* Some of these prerequisites may change as we get closer to releasing the beta version.

We will continue to update with new mods, ideas, insights and cool add-ons. So check back often and dont miss out on all the good things to come.

Update: October 21st 2013
I recently purchased a bunch of GT2 belts and pulleys so I thought I would try switching over the XL to use this setup as it is a more preferred method of linear motion, at least in my opinion. I had to make 2 idlers for each axis and mount them. I will also have to make mounts and tensioners for both axis’s. The reason for the idlers is so that the belts teeth will grip the pulleys as much as possible. The more teeth the belt grabs at one time, the better it is for your bot. I started making mock-up versions to make sure that my ideas will work correctly in a real world environment. After the mock-up versions are proven to be viable, I will make them look at little more polished. Eventually I will probably make printed versions of this setup as well. Here is what I’ve got so far and I will make sure to update as I go.


Update: October 22nd 2013
Hopefully today will be the day that we get to test out the new GT2 setup but, there are still a few modifications that need to be figured out. I cut some covers out of 1/4″ Lexan which will serve as the outermost belt guards. The new guards fit correctly but need to be tuned in for correct alignment. I am also finishing up the dual extruder beta today so it’s been a sort of back and forth between the two machines. My goals for the Simple XL today is simple: Finish guides, figure out tensioners, start design for final covers and mount everything so that the guides can be tuned in.

I also decided to add high tension springs on the x and y axis’s belts. This will help to take up any stretching of the belts which will also keep the belts taunt under any conditions. I’ve used this setup on several different bots and it has worked very well in the past. The only down side is implamenting the springs into any setup that wasn’t originally designed for it. The Simple XL is a great platform for this kind of modification. I will update soon with pictures and further explanation of mods.

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