# Shredder Drive

(Redirected from Open Source Shredder Calculations)

## Contents

# Calculations

- Largest force comparison- 15,000 in lb or 173 kg m. (1730 Nm) for the 45.6 Cu In Hydraulic Motor that we use in LifeTrac

# Shredding Rate

- Precious plastic shredder - what is shredding rate of precious plastic shredder? 3kw, 50kg/hr. [1]
- By comparison, we have 5W steppers. Minebea_Stepper_Motor_Specs
- This allows us for 3000/5=600x less throughput. This means that for 12 hour run time, we get 1 kg of shred.
- This is minimal, but doable for production or 2 filament spools/day. This means. $1200 revenue/month if selling spools at $20/spool.
- This is a mere 5W. Use 100W - and get 10x-20x the production rate - of 20-40 spools/day. That is a potential business.

# First Order Shaft Torque Calculations

- 1" shafts made of mild steel would break at 3000 ft lb of torque (ref?)
- Minimum torque requirement 200 ft lb, or 28 kg m. This is 1/6 the strongest motor.
- Precious Plastic Shredder calls for 3 kg m from Lyman_Filament_Maker_Calculations#More. But that is old - and apparently not enough. The PP Pro shredder calls for 100 kg-m torque.

# Motor Torque

- Motor Torque Calculator says about 1 kg m for 3000 rpm with 3kW drive as in Treadmill Motor. Compare to 173 kg m for strongest torque relevant to tractor drive as in 15000 In Lb Motors.
- Our goal is in between for now, 30 kg m. Reduction of only 30x to 100 RPM.

# Geardown

## Belt Geardown

- Serpentine belt on D=1.3" shaft of Treadmill Motor

# Motor Choices

Try a treadmill motor (3kW) and a drill motor (100W).

- Brushed motor is 75-80% efficient. [2]
- We can try a small DC motor, 30W. This yields a theoretical 12 kg per 12 hour day grind rate, which is just about correct. [3]
- Ex. JYCRS390H - [4]. Not 30W. Appears to be 5W - [5]

# Cost

- Square tube - 3/8" wall - $27/foot. (1/2" wall weighs about 27 lb)
- Round tube, 5 mm wall (0.188") - $25/ft [6]
- 1" pipe, about $2.60 per foot (1.25 OD, 0.125 wall) - [7]
- 2" schedule 40 - $35 at Menards [8]