What does this bottle cutter do?
This machine cuts recycled plastic (PET) bottles into rings or spirals with a heated knife in a safe enclosure that can be used safely by everyone.
Why did we make this and who is it for?
We are a group of Industrial Design Engineering students from Belgium. For our product engineering course we had to design a machine that can help kids with general learning disabilities convert recycled materials into art.
Here safety was very important because we don't want little kids to hurt themselves, but it also had to be fun and engaging. After a couple of user tests we came up with the BOTTLE CUTTER 2000.
If you have any questions or any suggestions to improve our design, please let us know in comments below
Can I build it?
This project requires good knowledge of electronics, skills with the soldering iron and access to a lot of prototyping machines and tools. You'll be working with dangerous voltages, be sure you know what you're doing!
Have fun building it!
Step 1: Gather All the Parts
• 12x MDF laser cut panels, thickness: 6mm
• 1x Fan 120x120mm (see datasheet)
• 1x Ventilation holes 120x120mm
• 4x bolts M4, length: 40mm (for fan mounting)
• 1x Carbon filter (see datasheet)
• 5x L-irons, length: 40mm
• 20x Screws, length: 6mm diameter 3mm
• Wood glue
• Aluminium tape for safe space
• Aluminium tape for bottom floor
• 6x Rubber feet 30x25mm
• 6x screws for rubber feet, length: 20mm, diameter 3mm
• 2x MDF laser cut frame, thickness: 6mm
• 1x PMMA laser cut plexiglass thickness: 1.5mm
• 16x M3, length: 16mm bolts
• 1x piano hinge, length: 20mm
• 4x screws for fastening the piano hinge to the door, length: 12mm diameter 3mm
• 4x M4, Length: 12mm Bolts for attaching the piano hinge to machine
• 2x Magnets with diameter 4mm and thickness: 2mm (see datasheet)
• 1x bracket for lock 3d printed (see 3d printed files)
• 1x Magnet for bracket, length: 7mm diameter 4mm (see datasheet)
• 2x screws for lock clamp length: 15mm diameter 2.5mm
• 1x Reed contact (see datasheet)
• 1x Electric lock 12v (see datasheet)
• 1x Fastening bracket lock and reed contact (see 3d printed files)
• 2x screws for mounting bracket lock, length: 16mm diameter 2.5mm
• 1x Handle 3d printed (See 3d printed files)
• 1x screw for handle, length: 15mm diameter 2.5mm
• 1x rotating laser cut wheel MDF, thickness: 6mm
• 1x Axle aluminium rod diameter 8mm, length: 80mm
• 1x Fixed for fixing disc on shaft
• 1x 3D printed mounting disc (see 3d printed files)
• 8x screws for 3d printed attachment disc, length: 12mm diameter 3mm
• 1x Handle woodturning
• 1x screw for handle, length: 60mm diameter 4mm
• 2x washers for the screw handle, thickness: 1.5mm diameter 12mm
• 1x Key switch (see datasheet)
• 1x Sliding Potentiometer (see datasheet)
• 1x Rotary switch 2 positions (see datasheet)
• 2x Arcade Push button green and red diameter 60mm with LED lighting
• 1x Emergency stop button (see datasheet)
• 1x Wooden block, length: 120mm, width 60mm, thickness: 32mm (see technical drawing)
• 1x DC motor (see datasheet)
• 2x toothed belt wheels GT2 (see datasheet)
• 1x GT2 300mm toothed belt (see datasheet)
• 2x Bearings (see datasheet)
• 1x Bearing housing (see 3d printed files)
• 4x screws for 3d printed bearing housing, length: 12mm, diameter 3mm
• 1x Block 3d printed (see 3d printed files)
• 1x Arm 3d printed (see 3d printed files)
• 1x Feeler1 3d printed (See 3d printed files)
• 1x Feeler2 3d printed (see 3d printed files)
• 1x limit switch (see datasheet)
• 1x Heated cutting element from pyrograph (see datasheet or product description + cutting point shape and cutting heat)
• 1x Servo motor (see datasheet)
• 1x aluminium block (see technical drawing)
• 1x Bolt M3, length: 5mm
• 1x spring (see datasheet)
• 1x Axle diameter 2.5mm, length: 30mm
• 2x screws for fixing servomotor (length: 10mm diameter: 2mm)
• 1x Servomotor attachment (see photo)
• 2x diameter: 1mm, length: 5mm screws, for fixing attachment servomotor to support cutting arm
• 1x support block cutting arm 3d print
• 2x 12mm diameter, length: 3mm screws on the cutting arm on aluminium block
• 1x Axis for the cutting arm support block, length: 27.5mm diameter 2mm
• 1x cover block 3d printed (see 3d printed files)
• 1x Cable chain 7x7mm, length: 720mm
• 1x Lead screw T8, length: 600mm (see data sheet)
• 1x Lead Screw Nut for lead screw T8 (See datasheet)
• 1x guide rod, length: 600mm diameter 8mm
• 1x Pillow block bearing (see datasheet)
• 2x Screws for fixation Pillow block bearing, length: 12mm diameter 3mm
• 2x Support for guide shaft 3d print
• 4x screws for fixing support blocks, length: 219mm diameter 4.2mm
• 1x coupling from the lead screw to the stepper motor 5-8mm
• 2x screws for attaching the cable chain, length: 12mm diameter 3mm
• Block for the limit switch in safe position, length: 60mm, width 40mm, thickness: 37mm
• 1x stepper motor unipolar (5 wires)
• 1x DC motor (5-12V) with gearbox (1-5 rpm)
• 5x Resistor 10KΩ 1 / 4W
• 1x Resistor 100KΩ 1 / 4W
• 5x Resistor 1KΩ 1 / 4W
• 2x Resistor 180Ω 1 / 4W
• 5x Resistor 3K9Ω 1 / 4W
• 3x Trimming potentiometer 10K linear
• 6x Flyback diodes
• 5x Mosfet STP16NF06L n-channel (60v 16A)
• 5x Transistor BC547B NPN (45v 100mA)
• 2x PIC16F88 (18pin microcontroller)
• 1x Relay 5v NO
Step 2: Laser Cut the Panels (or Saw Them by Hand)
Step 3: 3D Print Some Needed Parts
Step 4: Make the Frame From the Panels and 3D Printed Parts
Use wood glue to glue the main panels together at the finger joints.
Screw the door parts together with the Plexiglas part in between, then screw the hinge on the back side of the door and the 3D printed handle on the front of the door.
Screw the wheel onto the 3D printed wheel mounting disc, which in turn you can mount on the 8 cm long axis (diameter: 8 mm) which is connected to the small DC motor.
Screw the wood turned handle onto the wheel using a long 60 mm M4 screw with the 2 washers in between.
Step 5: Load the Software Onto the Micro-controllers
Load these 2 programs onto the micro-controllers to make the machine control all the electronic components.
Step 6: Assemble the Electronics
Use a voltage supply (5VDC and 12VCD(depending on the voltage of the DC motor you use)) that can handle the current that your motors draw. An old PC power supply should do the trick.
Be sure to add decoupling capacitors (100nF) next to the microcontrollers. All buttons connect, when pressed, 5v to the corresponding pin of the microcontroller. Add pull-down resistors (10k Ohm) to make sure detection works properly.
All the electronics should go into the enclosed right compartment of the housing with only cables going through the wall for the heating element, limit switch and RGB LED-strip.
The DC motor to turn the bottle and stepper motor to turn the lead screw are also in this compartment with their axle sticking through the divider walls. The other DC motor to detect the rotation of the wheel is also in here mounted on the inside of the right-side panel. This compartment also has a small door on the back for maintenance where a simple key lock is also advised to keep children from accessing the electronics.
Step 7: Put the Cutting Arm Together
- The lead screw nut is screwed onto the 3d printed arm holder.
- The heated cutting element is mounted into a small square aluminum extrusion profile with a few holes drilled into it (technical drawing included). It is secured tight by a small screw on the top of the profile.
- This extrusion profile is in turn assembled together with the 3d printed parts, the stepper motor and a small axle as shown in the illustrations.
- Put the small spring on the small hooks of both of the 3d printed cutting arm parts
- The limit switch can be mounted onto the two small pins on the side of the cutting arm.
- The cable chain should contain both the cables from the heating element and the limit switch and can be screwed onto the small protrusion of the printed cutting block.
- Now the entire cutting arm can be mounted onto the 60 cm long lead screw and guide rod
- The lead screw is coupled on the one side to the servo with the which is behind the separation panel, on the other side goes through a bearing which is mounted into a 3d printed bracket.
Step 8: Guide (how to Use the BOTTLE CUTTER 2000)
Children should always use the machine under the supervision of an adult. When detecting irregularities, do not hesitate to press the emergency stop (on top of the machine). To use the machine again afterwards, turn the emergency stop a little clockwise.
1. Switch on the machine by means of the key contact in the upper right corner. a. The light will NOT turn ON and the PUSH BUTTONS will NOT light => The power cable is not properly inserted, or the emergency stop (on top of the machine) has been pressed. Check power cable and / or emergency stop. b. The light does NOT turn ON and the RED PUSH BUTTON LIGHT => Electronically defective, contact crew. c. The light turns RED => The door is not closed (properly). Close the door. d. The light turns BLUE => The machine is starting up. Wait until the light turns WHITE and the GREEN PUSH BUTTON lights up. This can sometimes take a while
2. Open the door and screw a PET bottle into the holder. Make sure the bottle hangs horizontally. Close the door. a. The RED PUSH BUTTON remains lit => The door is not properly adjusted. b. The GREEN PUSH BUTTON lights up => The machine is ready to start.
3. Press the GREEN PUSH BUTTON. The light will color BLUE while the machine measures the bottle and puts the cutting arm in position.
Note: From this step you can stop the cutting operation at any time by pressing the RED BUTTON. The light will then turn RED while the cutting arm is moved to a safe position. Do not open the door until the light turns WHITE again, and start again from step 2.
4. When the light turns GREEN the machine is ready to cut. Make your selection between rings or a spiral, set the desired thickness, and turn the wheel clockwise. The machine will cut as long as it is turned, and pause when you stop spinning. a. Press the RED BUTTON if you have cut enough and wait until the light turns WHITE to open the door, or; b. Keep turning until the whole bottle is cut. The cutting arm will detect the end of the bottle and move it to the safe position. You can open the door when the light turns WHITE.