3D Printing Using Flexible Filament (TPU)

Through my short journey with 3D printing, I’ve spent a lot of time reading through the 3D Printing SubReddit and something that I found interesting was people talking about printing using flexible filament (TPU). While I didn’t have a real use for printing squishy things, I was curious. A few weeks ago, I purchased a roll of SainSmart Flexible TPU filament to see if I could print.

The forums and other references indicated that printing flexible filament was difficult because pushing the filament through the printer was like pushing a wet noodle! Some people had said that they printed with the stock printer, others said that for best results they modified the printer into a direct drive system. I was up for the challenge!

Before I started, I had already made the following modifications to my printer:

  • Replaced the extruder with an all metal one

  • Replaced the Bowden feed tube with a Capricorn one. The basic gist behind this change was that the tighter tolerances on the tubing doesn’t allow the filament to wiggle around and bunch up. In addition, when switching filaments, I don’t have to purge as much filament as very little gets stuck in the tube.

  • Added a filament guide that I printed. This should create a smoother path for the filament.

  • Added a filament runout sensor with guide. The main goal with this modification was to be notified when filament runs out so I can change it during a print. It also really helps feed the filament (with the flexible filament, I have to push down the microswitch to feed it).

  • Added a filament holder with bearings. This took awhile to print, but has been great. On my first flexible print, I noticed the extruder was having trouble pulling the filament because the roll wasn’t spinning freely. I helped things along, but realized that reducing friction would be a big help.

  • Leveled the bed manually and with the BLTouch.

Other than that, I’m using the stock magnetic bed that I cleaned.

My Cura settings are pretty straightforward.

For the TPU material settings, I used:

  • Print temperature: 215°C
  • Build plate temperature: 50°C

Profile settings:

  • Infill density: 10% (I was printing something squishy)
  • Print Speed: 20 mm/s (I’m going to try increasing this as things worked well)
  • Regular Fan Speed: 0%
  • Regular Fan Speed at Layer: 1
  • Material Flow: 110%
  • Enable Retraction: Off

That’s really all there was to my settings. Since I’m sometimes not the most adult person, I thought it would be funny to print a Poop Emoji for my son. It was squishy (10% infill) and I printed it at 50% of the original size keeping the print time to about 2 hours. My son absolutely loved the print. I was amazed at the print as I did it on the first try with my cold printer.

I’m going to keep experimenting with TPU and try to figure out what else I can print. I have no need for flexible filament, but why not print more stuff!

Installing a BLTouch on an Ender 3 Pro

I recently purchased a Creality Ender 3 Pro 3D printer as an “upgrade” to my Monoprice Select Mini Pro printer. There were a few reasons I decided to do this:

  1. Larger print area. While the Select Mini Pro is a great little printer, I am limited to what I can print and I’ve started getting interested in printing lithophanes which can get a bit larger than the printer can handle.
  2. Automatic bed leveling has no fallback. The Mini Pro uses an inductive sensor for automatic bed leveling and if that fails, I either have to replace it or am pretty much out of luck (someone has posted instructions on how to level the bed if the sensor fails, but it is a tad cumbersome).
  3. No ability to switch out the build plate for glass or another material. I’ve done a lot of reading about 3D printing and people swear by glass build plates and the Select Mini Pro doesn’t make it easy to add one. A shim has to be added to the Z axis limit switch and then you have to figure out the bed leveling.
  4. Limited to what filament types can be used. The printer has a maximum build plate temperature of 70°C and limited nozzle temperature which can limit the filaments used. Also, I’ve read that while some people have had success with TPU (a flexible filament), it may not work so well.
  5. No ability to modify the firmware for different features. The Ender 3 runs the Marlin firmware which is open source and can be easily modified.

In any case, I’ve read about manual bed leveling and while doable, it seems like a lot of work and I like easy! After setting up the printer and running it for a few days, I decided to install the BLTouch automatic bed leveling probe. In the weeks leading up to setting up the printer and the probe, I had read numerous articles and watched a number of videos on the subject, so I thought I was prepared for it. Parts of the setup seemed a bit daunting, but nothing I couldn’t handle.

The first step to installing the probe was printing out a mount for it. Thingiverse has a number of options. I settled on this mount as it was adjustable. Printing it and attaching the BLTouch was quite easy; I didn’t have the right size M3 screw, so I had to cut off a longer one.

After attaching the BLTouch, I had to run the extension wires through the sleeve that had the other wires. This was a little bit of a pain. The only mistake I made here that bit me later on is that the extension cable became disconnected and the BLTouch failed to operate causing the nozzle to hit the build plate. Oops. The lesson here was to hot glue the connectors together so that any jiggling of the cables wouldn’t cause them to disconnect. The second lesson is to always make sure the BLTouch performs its self test when the printer powers up.

Fhew, I’m exhausted just writing that up! After the wires were run, I had to attach them to the motherboard. The BLTouch has 2 connections; the first is done through a pin 27 connector and is just unplug the LCD cable, plug in the connector, plug in the LCD again and attach the 3 wires from the BLTouch making sure the orientation was correct by verifying the labeled pins were attached to the correct, color coded wires. The second part of attaching to the motherboard was to replace the Z axis end stop. The extension cable I bought had a non-keyed connector that just plugged in. Unfortunately it wasn’t a secure connection so I used hot glue on it the first time I connected it. On my second poke at the motherboard (due to troubleshooting the connector that came loose as I mentioned earlier), I decided to just cut the wires on the Z axis end stop, solder on the extension cable and use some heat shrink tubing. I had to make sure the white wire was towards the front and the black wire was towards the back. This was a much better connection and has less of a chance of coming close. After I buttoned up the motherboard, it was onto the firmware.

Once I initially got the printer setup and running properly, I upgraded the firmware mostly to know that I had thermal runaway protection and had the latest changes. Compiling the firmware was straightforward and explained in various posts and videos. Most of the posts talk about installing the initial firmware with a bootloader using an Arduino board. As I don’t have any Arduino boards around, I opted for installing using a Raspberry Pi 3B that I purchased to run OctoPrint. I used this guide which was easy to follow and perform the initial install. The printer didn’t come with a boot loader which required the extra steps to install the firmware the first time; why this was done, I have no idea. Over the course of a few days, I managed to pick the options I wanted for my firmware. Unfortunately my Creality 1.1.4 board doesn’t have much space on it, so I had to disable SD card support. This wasn’t a big deal as I do all my printing through OctoPrint. Using the base Ender 3 Marlin 2.0.1 example, I made the following changes:

Old Configuration.h:

    #define SHOW_CUSTOM_BOOTSCREEN
    #define BAUDRATE 115200
    #define CUSTOM_MACHINE_NAME "Ender-3"
    //#define BLTOUCH
    #define NOZZLE_TO_PROBE_OFFSET { 10, 10, 0 }
    #define MIN_PROBE_EDGE 10
    #define Z_PROBE_SPEED_FAST HOMING_FEEDRATE_Z
    #define Z_CLEARANCE_DEPLOY_PROBE   10 // Z Clearance for Deploy/Stow
    //#define Z_MIN_PROBE_REPEATABILITY_TEST
    //#define PROBING_FANS_OFF          // Turn fans off when probing
    //#define AUTO_BED_LEVELING_BILINEAR
    //#define RESTORE_LEVELING_AFTER_G28
    //#define LEVEL_BED_CORNERS'
    //#define Z_SAFE_HOMING
    #define SDSUPPORT
    //#define NOZZLE_PARK_FEATURE
    //#define SLIM_LCD_MENUS

New Configuration.h:

    //#define SHOW_CUSTOM_BOOTSCREEN
    #define BAUDRATE 250000
    #define CUSTOM_MACHINE_NAME "Ender 3 Pro"
    #define BLTOUCH
    #define NOZZLE_TO_PROBE_OFFSET { -44, -16, 0 }
    #define MIN_PROBE_EDGE 44
    #define Z_PROBE_SPEED_FAST HOMING_FEEDRATE_Z / 5
    #define Z_CLEARANCE_DEPLOY_PROBE   15 // Z Clearance for Deploy/Stow
    #define Z_MIN_PROBE_REPEATABILITY_TEST
    #define PROBING_FANS_OFF          // Turn fans off when probing
    #define AUTO_BED_LEVELING_BILINEAR
    #define RESTORE_LEVELING_AFTER_G28
    #define LEVEL_BED_CORNERS
    #define Z_SAFE_HOMING
    //#define SDSUPPORT
    #define NOZZLE_PARK_FEATURE
    #define SLIM_LCD_MENUS

Old Configuration_adv.h:

    //#define BABYSTEP_DISPLAY_TOTAL          // Display total babysteps since last G28
    //#define BABYSTEP_ZPROBE_OFFSET          // Combine M851 Z and Babystepping
      //#define BABYSTEP_ZPROBE_GFX_OVERLAY   // Enable graphical overlay on Z-offset editor
    //#define ADVANCED_PAUSE_FEATURE

New Configuration_adv.h:

    #define BABYSTEP_DISPLAY_TOTAL          // Display total babysteps since last G28
    #define BABYSTEP_ZPROBE_OFFSET          // Combine M851 Z and Babystepping
      #define BABYSTEP_ZPROBE_GFX_OVERLAY   // Enable graphical overlay on Z-offset editor
    #define ADVANCED_PAUSE_FEATURE

Downloading the firmware after the first install was easily done through OctoPrint without having to install jumper wires and remove the motherboard. It is so easy that I made changes, recompiled, and uploaded new firmware a few times.

Was I done yet? Of course not! I hadn’t even leveled the bed! Some guides say to add a G29 command to Cura settings which runs the auto bed leveling on every print. Auto bed leveling is slow and that’s just a waste of time. So I decided that I’ll just level the bed every few days. I started up the printer, did an Auto Home, verified that touching the probe sent the hot end up (if it didn’t, I would have stopped the printer). Using OctoPrint, I sent

G28; auto home

G29 L50 R150 F50 B150 T V4

to the printer to start the auto bed leveling. This sets a bit wider grid than the default G29 command. Then I sent a

M500

command to store the settings.

M501

to read the settings back.

Was I finally done? Nope. The next piece in the BLTouch configuration was to properly set the Z Probe offset. This is the distance between the bottom of the nozzle and the bottom of the probe. The probe is, obviously, slightly higher than the nozzle (so that it doesn’t drag). Most guides say to start at zero, print a first layer, adjust the Babystep Z, use the M851 command and then store the setting. I did this and after a number of adjustments, got things printing quite well. However, after reading this manual bed leveling guide, I realized that there was a slightly easier way. Basically if I have an object of a known size, i.e. a cube that I use calipers to measure the height, raise the Z axis (using the controls on the printer), put the cube directly under the nozzle and adjust the Z axis so that the nozzle barely touches the cube, I’d know exactly the Z Probe Offset. If the cube is say 15 mm tall and the Z axis shows 15.88 mm, I’d set the Z Probe Offset to be -0.88 mm. So much less guess work in this. Don’t forget to store the settings after setting the Z Probe Offset. Since my settings are pretty good using the Babystep Z (with my firmware options simply called Z Probe Offset), I haven’t actually tried using a cube of known size to set the offset.

Lastly, I used the Level Bed Corners menu option I enabled in the firmware to manually level the bed as well as I could and then re-did auto bed leveling so that the firmware would have less to compensate. In addition, I used the OctoPrint Bed Level Visualizer plugin to see how close I got to a level bed. I know that the bed is going to warp at some point, but for now I have a pretty flat and level build plate.

Even after I had everything setup, I discovered that my bed was much higher on the right side even though when I had manually leveled it, it was pretty good. It turns out that my X gantry was loose so the right side was higher than the left. There are plenty of videos that explain how tighten this; don’t follow the Creality video as it is pretty useless.

To summarize, here are my tips:

  • Use hot glue on the extension cable connectors.
  • Splice in (and solder) the extension cable connectors (black and white wires) to the Z axis end stop.
  • Compile your own firmware so that you can get the settings you want.
  • Don’t put the G29 code in your Cura profile as that is a waste of time; level your bed every few days if needed.
  • Manually level your bed after everything is setup and then re-run auto bed leveling.
  • Check to make sure that your X gantry is tight.
  • Use a known height object, i.e. a cube to set the Z Probe Offset.

Of course, follow my directions/tips at your own risk. I’m not an expert at this and am not responsible for any problems arising from your use of this information! I thought I had everything working well until I managed to crash the nozzle into my bed (I now have a nice dent in the bed that I’ll bed around to replacing someday).

Good luck as getting BLTouch working properly isn’t an easy task, but hopefully worth it in the long run!

Review: ParkZone Night Vapor

My interest in RC flying vehicles hasn’t stopped at helicopters. My wife bought me a ParkZone Night Vapor for Hanukkah. This plane is advertised as an intermediate plane, but also could be flown indoors. As I don’t have a back yard large enough to fly other planes such as the HobbyZone Champ, I thought that the Night Vapor would be cool to fly.

The first day that I tried to fly it, I had very little success; I flew it in the living room and was not able to maneuver it to turn it. A few weeks later, my father, son, and I spent a few hours flying in my garage (it’s a great place to fly when both cars are removed) and I started to get the hang of the Night Vapor. Since then I’ve spent more time flying and have gotten quite good at making turns in tight places. Today I flew it outside and managed not to crash it too much! My only slight problem is that I almost landed it in the pool, but other than that, I was doing pretty well. Of course, flying an RC plane is a lot different from helicopters. Planes need more space, has no reverse, and can’t turn on a dime. It is taking me a bit of practice to go from frustration to having fun. The hardest part for me is to remember that if I want the plane to dive, I need to push the right stick forward and not back.

While I’ve crashed the plane quite a bit, I’ve only had to do minor repairs on it. I had to replace the main motor (I think it was defective from the factory) and one of the gears. In addition, my dog wasn’t too happy when it flew close to him and he bit it ripping a small hole in it; clear packing tape fixed it right up. I’m quite surprised how durable it is despite having cellophane wings.

Pros

  • Very durable.
  • Flies in small places.
  • Flies well outside.
  • Not too hard to control once you get a hang of it.
  • Long battery life compared to the helicopters (I can get about 15 minutes out of a battery)

Cons

  • None

Summary

The Night Vapor is a lot of fun to fly indoors and out. I’m not sure that there are too many RC planes that can fly in relatively small rooms or a garage. The plane takes a little getting used tobe, but after a few flights, it gets a lot easier to handle. While I really enjoy flying the helicopters, flying this plane is a different experience that has its own joys. The extended flight time (about 2.5 times longer than the helicopters) is probably the biggest reason I’ve been flying it more. I have multiple batteries, but having to stop and change the batteries takes some of the fun out of the helicopters. Beginners might get a little turned off when they crash and get afraid of destroying it, but once they get over this, this plane can probably be flown by beginners.

Excellent customer service

As it is probably apparent, I’m a bit addicted to my new hobby and bought another helicopter. This time it was a Blade mSR. I flew it a few times and it flies pretty well. However, after those flights, I started seeing a problem where the helicopter looked like it was periodically losing power during flight.

I read a post where others have experienced the same problem. I contacted Horizon Hobby support describing the problem and referencing the post. They promptly replied, asked for pictures of the motor and a copy of my receipt. The day after I replied with the information, I had a new tail rotor and new main rotor in my hands at no cost and they didn’t require me to send the parts back!

I was quite pleased with the service and definitely will keep me buying Horizon Hobby products. It makes perfect sense for a company to provide excellent customer service to keep you coming back for more. However, so many companies don’t quite understand this. In this case, I paid just over $105 for the helicopter and they sent me about $20 in parts without having to send anything back and with no down time. For someone addicted to a hobby, they just help me feed my habit.

Review: Blade CX3

First off, I have to admit that I’m getting addicted to RC helicopters which if I don’t watch myself is going to get quite expensive! Now that I have that off my chest, I’ve now purchased my third helicopter, this time a Blade CX3. This helicopter is a huge step up in terms of size from my Blade mCX2.

When I first got the helicopter, I was a little afraid to fly it. The bigger the helicopter, the more it would cost to repair. I flied it around my office a little bit, but due to its size, it’s pretty hard to do much with it. However, I did get the hang of it (it’s quite loud) and decided to give it a whirl outside. Well, I was a bit overconfident and on my first flight outside, it ended up on the roof and I caught it as it came crashing down on me. Luckily I was able to repair the fuselage damage with some clear tape and it was as good as new.

I’ve been having a lot of fun with it and am excited to fly it outside. However, there has to be very, very little wind to do anything with it. The times I’ve flown it outside, the wind is just a little too strong so that when I try to go forward full speed, it goes no where. It is teaching me how to control it in adverse conditions which is kind of interesting.

One of the maneuvers  that I’ve pretty much perfected on the mCX2 is landings in a single spot. On the CX3, this is much harder because of the ground effect created by the blades; flying it low is kind of difficult due to this (the blades are pushing down a bit of air causing the helicopter to go up). This is something that I’m keep attempting.

The CX3 doesn’t use anything that is the same as my mCX2, so I’ve already started collecting spare parts in the event of a crash. I’ve also had to pick up an extra battery as the 6 minute flight time is a bit short when it takes 2 hours to recharge the battery.

Many of the points below are similar to what I wrote about the mCX2. The two helicopters are quite similar as beginner helicopters.

Pros

  • Not too hard to control.
  • Moderate size allows me to fly outside.
  • Replacement parts aren’t that expensive.
  • Comes with battery charger.
  • Heading hold gyro attempts to keep the nose facing in the direction of travel.
  • It’s quite fast when flying inside.

Cons

  • Size makes it a bit large to fly inside and do anything interesting (very small circles).
  • Only comes with 1 battery.
  • Long recharge time (2 hours).
  • Navigation lights are optional (they look cool on the mCX2).
  • It’s noisy. In the house, it’s hard to really hear anything when it’s flying.
  • Time consuming to disassemble. I added a heat sink to it and it took me about an hour to take it apart and install the heat sink. Maybe it was just me, but I had a problem removing one of the motors to get the heat sink in.

Summary

The CX3, like the mCX2, is a beginner helicopter. I kind of see it as a stepping stone from the mCX2 as it is larger and can fly outside. I’m glad that I got the mCX2 first as it let me learn to fly and maneuvers. I haven’t abandoned my mCX2, but I find the CX3 a bit more challenging and more exciting. If you’re interested in RC helicopters and don’t have much room to fly, the mCX2 is the way to go. If you have more room and want to fly outside, the CX3 is the better choice.

I’m having a great time with my helicopters and am getting pretty good at flying.

Review: Blade mCX2

After getting a Syma S107 RC helicopter, I was quickly hooked on RC helicopters. I went to the local hobby shop, Discount Hobby Warehouse, and took a look at the Blade mCX2. When I mentioned to the guy at the shop that I had a cheap $30 helicopter, he said that the goal of the cheap ones is to not crash while the goal of the more expensive ones is to fly. I definitely could agree to the part about not crashing. I bought it and when I got home, I charged the battery and was off and running. I was easily able to fly it around for a few minutes until the battery died (I get about 6 – 6 1/2 minutes per charge). I’ve picked up a few more batteries and have been spending at least 20-30 minutes a day. I’m definitely a fan.

Everything I’ve been reading indicates that the coaxial helicopters (CX) are easy to fly and are beginner helicopters, so I think I picked the right one. The mCX2 is easy to fly inside (it is far too small to fly outside as the wind will knock it around). The entry price is reasonable (for a hobby), but the cost will quickly add up, so be prepared. I’ve already bought a few more batteries, a four port charger with AC adapter, and due to a crash, some spare parts.

Speaking of crashes, while the helicopter is easy to handle, if you want to start to get fancy, it’s quite maneuverable, so much so that it isn’t that hard to crash. I made the helicopter yaw a bit too much and then over corrected which lead to the crash. The crash cost me about $15 in parts to repair. Even though the parts are quite small, repairing it, isn’t that hard. It comes with a small phillips screwdriver and combined with a pair of locking forceps  that I got at an Army/Navy Surplus store, repairs just take a little time and not much skill.

The mCX2 uses parts that are shared with other helicopters made by Blade, such as the mSR and mCX Tandem Rescue, so if you get one and want to upgrade, you already have some pieces.

Pros

  • Compact size allows you to fly in the house.
  • Easy to control.
  • Captivating (I’m really hooked).
  • Challenging. While easy to control, I’m teaching myself how to land it in a small area which is proving to be easier said than done.
  • Easy to repair.
  • Individual parts aren’t that expensive.
  • Relatively durable. It handles small crashes well.

Cons

  • Price. Some may say that the price is a little high. I think the entry price isn’t bad, but it starts adding up quickly.
  • Only comes with 1 battery.
  • Short flight time. Due to the small size of the helicopter, it has to have a small battery, so this is understandable.
  • Only comes with a 1 port charger. Charging 1 battery at a time means you have to wait 30-40 minutes for it to charge between flights.
  • Charger runs on 4 AA batteries; AC adapter is optional. The manual says that the AA batteries will charge the battery 15-20 times. Since I started with 2 batteries, and I flew it as often as possible in the first few days, that the batteries only lasted 3-4 days. This cost savings is not very green and is extremely annoying. I went ahead and got a 4 port charger with an AC adapter and now I can run through 4 batteries and then charge them all up.
  • It’s addictive.

Summary

For some reason, I’ve always been fascinated with things that fly. So, when I tried my first helicopter a few weeks ago, I quickly realized that I may have found a hobby (up until now, I really haven’t had a hobby as an adult). The mCX2 is a great entry level helicopter and provides hours of fun. If you think that the cost of the helicopter is the end of spending money on it, I wouldn’t get it. The costs will start adding up quite quickly. I mentioned this helicopter to a friend (he already had a few other helicopters) and he bought it based on me talking about it. He seems quite pleased with it as well (his dogs aren’t pleased with it, however).

This helicopter is not a toy, so heed the age level on the box (14 and up). I’m not sure it is appropriate for a 14 year old, however.

I’m very happy with my purchase and can definitely recommend it to anyone that has ever been interested in RC helicopters.

Review: Syma S107 RC Helicopter

As a child, I had RC (radio controlled) cars a few times and enjoyed playing with them. However, they ate batteries like no tomorrow and since they weren’t rechargeable, play time was quite short. Years later, the battery technology has gotten a lot better and rechargeable batteries are in almost everything. As an adult, I’ve owned an RC Hummer and an RC hovercraft, but have never owned a helicopter. I’ve always been fascinating with them; however, I never made the leap into owning one.

Last week I was looking for something on the Internet and came across an advertisement for a company that sells RC helicopters. After a little research, I found a very beginner helicopter, the Syma S107, for about $30. I decided to give it a try knowing that it was a toy and I didn’t expect a whole lot from it given that some helicopters I saw cost significantly more.

Once I received the helicopter, I plugged it into USB and charged it for 45 minutes or so. My first few tries were not very good and had hard or crash landings. The blades are quite durable and seemed to handle my poor flying (however, I did order some additional main blades and tail blades off eBay).

Flying a helicopter is definitely not like driving an RC car; once you take your finger off the throttle, it immediately falls to the ground and crashes. Also, hovering isn’t as easy as just making it lift off the ground and leaving it there. You have to continuously adjust it to keep it in one place. I’m now 3 days into it and am starting to make progress at controlling it. My office is quite large and allows me some room to fly, but I keep hitting my desk chair (yes, I should move) or the base of my punching bag.

This little helicopter has definitely piqued my interest in RC helicopters and I’ll be going to a hobby store later this week to start drooling (I’m looking at the Blade mCX2).

I’ve been searching for a hobby for years; my hobby has always been writing software. However, I’m not really sure I can consider my work a hobby! I’m excited enough, that this little helicopter may have opened my eyes to something I didn’t know could be fun.

Pros

  • Inexpensive
  • Durable main blades
  • Durable body and landing skids (haven’t broken then, yet)
  • Easy to charge with USB
  • Replacement parts are cheap and readily available on eBay

Cons

  • Infrared remote; you basically can’t fly it outside and fluorescent lights could interfere with control.
  • Short flight time
  • Manual is poorly translated from Chinese
  • A little difficult to master
  • A lot of drift even with no wind; this could be all RC helicopters, but from what I’ve read, the better ones are easier to hover in place
  • Tail rotor is easily broken (it comes with a spare, but I’m already using it)

Summary

For $30, this is definitely a fun toy. However, I wouldn’t consider it a child’s toy as it isn’t easy to control. My 3 year old son drives my RC truck, but I wouldn’t consider handing him the controls to the helicopter. If you’ve never flown an RC helicopter before, don’t expect to be flying perfectly on the first flight. It will take some time to learn the controls and master flight.

The biggest downside I can see to this is that after the first taste of flight, you’ll want to get something better!