- Motor type and quantity
- Current limit (A)
Motor
- Motor torque at limit and stall
- Free speed (rpm)
- Calc
Belt reduction to rack and pinion
Guide 1
The scrimmage failure: a NEO with a 15T pulley, 9 mm belt to a 32T printed pulley on 1/2 in hex, driving two 32T pinions on a rack. At a 60 A limit the 32T pulley sees about 3.1 N·m, and its printed hex bore still rounded out.
Belt tension is the same at both pulleys; torque is not. That is why the bigger pulley is where the bore fails.
Where the load goes — and where it fails
NEO at a 60 A current limit, slide jammed. Imperial first, metric in parentheses.
appliedcalculatedwatchfailure point
Losses ignored; steady stall at the current limit. A sudden jam spikes higher — see the shock factor in the calculator.
Stall torque flows down the chain; every joint gets a check
- Inputs
- Joint
- Calc
- Check
- Teeth
- Belt pitch, HTD 5 mm or GT2 3 mm
Drive pulley
- Pitch radius
- Teeth in mesh
- Calc
- Width, 9 or 15 mm
- Tensioner, yes or no
Belt
- Belt tension vs allowable
- Skip risk at the jam spike
- Check
- Teeth
- Material, aluminum or printed
Driven pulley
- Hex bore corner force
- Pass or fail for the material
- Check
- Length between pinions
- Steel or aluminum
1/2 in hex shaft
- Shaft torque
- Twist end to end
- Calc
- Teeth and pitch
- Material and bore type
Pinions
- Tooth force per pinion
- Pinion bore check
- Check
- Moving mass
- Shock factor
Rack and slide
- Push force at stall
- Slide speed
- Calc
What it teaches
Torque multiplies through a reduction, and the joint with the smallest contact area fails first, not the most obvious part.
Session hook
Students predict which joint fails first, run the numbers, then turn a printed hex pulley on a torque wrench until it rounds out.