Sweet Scoops Remix of the Chris Riley Candy Claw Machine

This will be long winded and detailed.  I'll TL:DR it as well as spell it out.


TL:DR
This will require you to also have all of Chris Riley's original Candy Claw Machine Project.
All of my STEP, STL, 3MF (OrcaSlicer projects) and photos are in the zip folder.
Printables made me add model files.  Just download the zip folder for everything.

Various pictures have differences due to design changes/updates.  The pics full of candy are the final design with all updates.  If it looks complete in the pic, the only changes were the addition of filagree, font change on the controller deck, and a reprint of the deck plates because of the change in joysticks.

If you choose to build one of these machines, especially my version be aware that various changes may have to be made by you to files/parts to accommodate your choices.  Even if you follow my project to a “T”, I may have missed updating some parts to work with other things.  I had to make a lot of adaptations because of mistakes I made due to my choices changing the design from Chris' machine. 

Don't be afraid to try to build one of these, but its not a quick or easy project.  (Roughly 4 months to do the vast majority of redesigning, eating mistakes, and building).

Rough cost to build one is ~ $500 if you need to buy nearly everything.

Used in my build:
- Chris Riley's Candy Claw Machine
     See his github and printables page for files and BoM and his Youtube channel for the assembly videos

- The display panel knob is from layer.works on Printables
- The geared hinges on the door are from E. Soderberg on Printables
- The slide bolt latches on the door are from 3dprintingworld on Thangs
- The ramps case is modified from rockstorm on Thingiverse
- Everything else was available from Chris' docs or my design 

Note: the filagree and fonts were also taken from the internet but I don't recall who or where but those were my personal customizations and I think those who undertake the claw machine build will likely customize it to their tastes and likely do the same - just want to be open and clear here.

Long Story

Chris Riley's Candy Claw Machine is an awesome project.  We wanted to get a claw machine for our kids as a means of rewards.  Unfortunately the cheap $50 ones were all terrible.  A real machine is minimum $500.  Vevor and now Arcade1Up are the only ones that sell them at this price and that is like a small candy machine you would see at an arcade.  To buy an actual used arcade machine meant that sourcing parts and figuring out how to fix it would be a huge hassle.  Most claw machines are very large too.  So a-googling a went for a printable machine, which is how I came across Chris Riley's machine.  The cost seemed to be cheaper because I had a printer I could salvage stuff from and other bits and pieces I've accumulated through the years.  THIS WAS MISTAKE 1.  It still cost us roughly $500 to build this.  BUT there is nothing like it.  It was a blast to work through.  I would still rather have this than the actual machines.

Starting on this road, Some of the critical parts on Chris' build require a 300x300 printer like a CR-10.  No prob.  I have a FLSUN V400.  The bed is 300 diameter.  It'll be tight but fine right?  MISTAKE 2.  You cannot print a square peg on a round printer… unless you scale.  which wasn't going to happen.  So from the start, I had road blocks.  But I reviewed the design and I had a nice piece of 1/2 inch plywood laying around that I could use as the machine floor, so I figured I could work this out.  The wood makes it sturdier and eliminates a bunch of printing time and filament use (MISTAKE 3 - I made A LOT of pieces that got ditched from design changes all throughout this build…).  But I had enough to get me through this and learn a bunch at the same time.  

Everything in my file set is printable on a 180 mm x 180 mm x 180 mm build volume printer with the exception of my power supply housing and cover.  I used a larger power supply from a Voxelab Aquila printer which then also required a buck converter from 24v to 12v for the electronics.  I don't suggest going this route.  I could have spent $4.00 more than the cost of the buck converter on the power supply Chris suggested and not need the buck converter at all.  I burned that savings in plastic.


Goals:

- Printable on a small volume printer (180^3 mm)  I have a Bambu Lab A1 Mini
- Print as much as possible
- Make things replaceable and easy to assemble as much as possible
- Victorian-esque, vintage look
- Black and White checkerboard tile floor
- Utilize the sweet hologram texture beds as much as possible
- As cheap as possible using on hand stuff (total FAIL.  disregard this goal).
- Access door
- Replaceable claw jaws
- Move the electronics off of the side of the machine/hide them
- As clean of a design as possible; leave gaps for fitment variations but design parts to cover gaps


Details:

This will be a summary of my design characteristics.  I am not going to do a thorough build log of how to build this exact machine.  If you need help building my remix, please reach out. 

- Screw lengths will vary quite a bit and head style is your choice.  I went with button heads for a cleaner yet still exposed look.  I primarily used M5 x 6, 8, 10, 12, 20, 25 mm long button heads.  I didn't write down what got used where so have a good selection on hand and quite a lot.  The main hardware for the kinematics are basically unchanged from Chris' BoM.

Oh you will need well over 200 M5 extrusion nuts if you use this design.  Its a lot of screws compared to the original.  But this is the trade off with the smaller parts and proper securing.

I started building the frame per Chris' design.  Silver classy looking extrusion for me.  
The cheap corner brackets I chose based off of Chris' BoM (not the ones linked in his BoM) kept breaking so I switch to printed angle brackets that I designed.  These are the same as countless others on 3D printing websites.  I just chose to model my own to hone my Fusion360 skills.  
There are several places where the use of angle brackets instead of corner brackets affected my design.  The use of the corner brackets affected my design as well (oversight on my part).  Some of my mounting hole locations were where the corner brackets were.  So I had to redesign shorter corner brackets to print.  NOTE: if you use angle brackets and want to stick to the original design of the machine from Chris, you MUST still use either printed corner brackets or metal ones.  The frame dimensions only work this way.  I learned this the hard way.

I chose to use the ½ inch plywood for a floor to stiffen the the entire machine as well as allow me to print simple thin floor tiles (checkerboard FTW).  Cut this to the outside dimensions of the built frame.  Its held onto the frame with the foot screws.  I have 8 total.  These are a custom size to fit within the outer dims of the frame so the side panels can completely hide the plywood and not be pushed out by the standard round feet.

Looking inside the machine floor, there are extrusion covers that also act as wire covers.  These were designed to cover the exposed wood from the gaps left in my tiles.  They didn't fit edge to edge inside.  I started at one corner and made sure they fit tightly together.  This way no wood is seen in the floor.  

Next, I figured out a way to make the side panels and dividers that still meet the 3 mm thickness of Chris' design including allowing for the same thickness of acrylic sheets.  The dividers are meant to be glued together and slid into place.  The dividers between the glass and lower panels are identical and tabbed to interlock.  Just glue together.  These don't need to be glued to the glass or lower panels.  The lower panels extend below the extrusion to cover the plywood so the panel dividers are longer on the outside to extend to the bottom.  These are designed to cover the gaps between each panel so that everything fits easily together but no big gaps are seen. They also have the same interlocking tab design.    The goal was guaranteed assembly without needing to trim things after printing regardless the dimensional accuracy of the prints.

The prize chute is a separate piece the mounts to the extrusion.  It also helps to stabilize things.   If you wind up using angle brackets, some angled shim parts will be needed.  If you use the tile flooring like I did, some shims will also be needed for the mounting ears of the prize box.  These files are included.  The ramp inside is shallow enough that a catch bin on the outside isn't necessary.  I didn't design one or print Chris'.  We haven't seen any candy or prizes fly out of it yet.  This is also due to the prize door being TPU flaps.  I took the idea from warehouses that use the large plastic sheet strips as a quick access wind barrier to large openings.  This setup uses two thin parts with strips coming down mounted to the exterior side panel.  These are printed in TPU.  Only 1 is necessary but I chose to double up just because.  The two parts for the flaps are offset slightly from each other to provide a move closed face.   

The kinematics are basically unchanged.  Just follow Chris' info for building the gantry, claw workings, etc.  The only difference here is the claw itself.  I modified the claw halves to accept replacement jaws.  This is so they can easily be printed in a different material separately and changed without having to rebuild the claw.  I've only tried the saw teeth but the TPU is working great.  I have flat blade jaws but I don't know if I will even try them.  I think I had to shrink the jaws by 1 mm lengthwise only to fit properly in the claws without bowing.  I don't think I updated the STLs or STEPs because this was such an easier fix in the slicer.  

I splurged on the mirror acrylic back because this is a common feature of claw machines but also allows everything to be hidden in the back.

I learned something important about the acrylic.  If you didn't know, this stuff can chip and crack easily when drilling.  Drill a normal pilot hole thats about 1/8 inch  (3 mm) then instead of drilling to the proper size (I like 5.5-6mm for an M5 screw to allow for adjustments) use a rotary tool with a cone shaped grinding stone.  The stone will melt through the plastic relatively cleanly instead of the harsh cutting edge of a drill bit.  I had to use the pillar trim to locate all of the screws holes because this remix differs from Chris'.  

The door was completely winged.  It had to be cut to a different width than the other sheets.  It's cut so it would sit just inside the vertical frame extrusions.  I wanted to printed everything I could so I found cool geared hinges from E. Soderberg.  Then I wanted to keep the door shut.  I was thinking magnets but also wanted to keep kids from easily getting inside.  I ended up using a pair of fully printed slide bolt latches with one inside and outside of the glass.  The top one is inside so you need to reach up and over while reaching the lower outside latch to open.  This would stop most kids from cheating, lol.  The latch is from 3dprintingworld.  The top latch slide engages inside of the extrusion (lucky!) and the lower required a printed 3 mm spacer for the catch on the vertical extrusion.  The pillar trim was modified for clearance of these parts and are not secured with screws on the door side of the machine.  I could have modified these more to sit flat against the extrusion by I left the pillar trims with the 3 mm gap for the acrylic.  The latches are hinges were positioned by simply winging positioning by eye, mark with a sharpie, drill, test fit, position as needed, mark, drill, test fit, etc.  Hey, it works.

The LED diffusers were cut up into evenly sized parts simply in the slicer then exported as STLs.

The top bar was cut up and extra mounting holes added.  The cuts were not 100% equal lengths because I wanted to use the display board as support to tie the left and center pieces together.  The center and right panels are tied together by the marquee backer.  I made and glued small squares between the seems of the sections on the top inside of the top bar to help strengthen the top bar.  Extra holes were added simply so there are 3 screws per section.  I also used a printable plate for the marquee instead of acrylic.  The marquee back being printed is just another bit of “print everything you can”.   The marquee backer is the same part with a lap joint on one end.  Simply print 2 parts the same, overlap and glue together.  This was a great opportunity to try full contact support with PETG printing the part in silk PLA.  The part is something like 1 mm thick overall and the lap joint is half that thick.  Its thin for light transparency.  Because I wanted to use the hologram textured bed, this would require one half to be printed with a large thin overlap (about 40 mm x 25 mm x .5 mm thick or so)  If I used normal supports it would have a rough surface and not bond flat so I tried using PETG as the support material.  Total win here.  It worked beautifully with the A1 Mini.

  The pillars were redesigned to be evenly sized with extra mounting holes to suit.  Some pillar parts were designed with cuts to fit my exact design around certain features like the door, controller deck, and controller board.

The controller box was completely redesigned and mounts directly to the extrusion instead of the dovetail style slide of your design.  There us a reinforcement plate on the bottom using M5 screws and nuts, then dovetail rails on the verticals with clips to tie the two controller box halves together.  I made a separate mounting plate to hold the ground and power bus bars that mounts to the inner wall of the box at the extrusion mounting locations for the box.  That's kind of hard to explain, but it mounts using the same screws that the box half is mounted with.  The bus bars are held to the plate with screws and nuts.  

The button setup is the same as Chris' and ultimately so is the joystick, wiring, etc.  
MISTAKE #3623.  The joystick.  Apparently with the Ramps board and Mega 2560 with the display module and using Marlin, your only option is an analog joystick using potentiometers.  If you get the microswitch style joystick, it won't work as far as I can tell.  I spent hours googling around trying to find a way to make it work.  The ramps/Mega doesn't have enough spare digital pins with the display, I don't know how to do this stuff, Marlin only supports analog joysticks, and possibly other reasons it won't work.  Unfortunately, it looks like the only arcade style joystick that uses potentiometers is the brand Chris has listed in the BoM.  I would suggest just buy this one in your color choice.  But as Olmec would say, “The choice is yours and yours alone.”

I used a Mega 2560 and ramps setup.  All clone parts, nothing genuine.  I bought a kit with everything I needed.  Then I fried the 5v voltage regulator and went crazy.  I've loaded Marlin before, but never dealt with an Arduino board fresh like this.  I'm savvy in a lot of things, but coding and the like, not so much. 
 
WARNING: If you use this board setup and are not familiar with it at all (like me), here are my mistakes.

- Read setup docs for the ramps carefully.  There are lots of walkthroughs and tips on setup because this was the defacto standard for 3D printing for a long time.  There is also lots of troubleshooting info out there for this stuff.

- Be careful not to install stepper drivers wrong.  I didn't make this mistake but it is clearly noted on all articles.

- MISTAKE: DON'T MISWIRE YOUR LIMITS.  If you have a limit connector pinned into the Ramps board backwards (doesn't matter which one) it will fry the 5v voltage regulator on the Mega board.  I had plugged them in correctly to the board, but I missed a crossed dupont connector at an extension.  As soon as you hook this up to power and feed the board 12v, it will instantly fry the 5v regulator.  My board took firmware and would connect to Pronterface.  It would only take an M119 command.  But all limits always showed open no matter the status.  Nothing worked.  This was at one time a common problem for people.  Several posts on forums mentioned people having a stockpile (because they are cheap) of 5v regulators to replace on dead boards because of it.  I bought some regulators, replaced it, AMS1117 5v is what you need if you are at this point :(

- I had to play games with the display cables.  Apparently not all clones have the display boards pinned out the same.  If you have something like the display not working when everything else does (you got past the fried voltage regulator), try swapping the cables connector 1 to connector 2, or also try removing the connector headers at the display board and rotating them 180°.  The pins should be board mounted, but the plastic headers are just press fit onto the pins.  Be careful not to bend the pins, but they should come off with some wiggling.  Rotate 180° so the alignment tab is facing the opposite direction and see if that works for you.

For board mounting, I chose to make a custom mounting plate and then remixed this Ramps case from rockstorm.  I made additional clearances for the display cables and added a zip tie lock.

The wires were all hidden with custom covers that mate to the pillar trim.

I used expando wire loom for my umbilical.  It gives a cleaner look than the spiral wrap but it can be a pain to work with… especially if you need to fix a loose connector inside of it (MISTAKE #7492).  Remember to tape up those connectors so they don't wiggle loose!

I think this is a fairly thorough summary of my changes.  There are plenty of small nuances that I forgot to add that would also make this so much longer.  I've typed enough.  If you need help, just ask.  I would be happy to help.

 

• Printable on a printer with a 180 mm x 180 mm x 180 mm build volume or larger (Prusa Mini and Bambu Lab A1 Mini - woot!)
• Many of the cosmetic changes are complete redesigns and additions to achieve the ability to print on a small printer as well as add little details (like wire covers).
• Some parts like the pillar trim were completely remodeled to the same dimensions as the original but accommodate a printer friendly length and additional screw locations
• The original but the kinematic design, function, and firmware of the actual machine operation is the unchanged.
• side door access
• replaceable claw jaws without rebuilding the claw