Question

A machine tool cylinder is connected regeneratively to give a rapid approach speed of 10 m/min for a stroke of 1 m with a theoretical thrust of 2.5 tonnes. It is then switched to conventional connection to provide a pressing speed of 0.25 m/min for 0.5 m with a theoretical thrust of 10 tonnes. The maximum pressure at the cylinder is to be 200 bar.

(a) Select a suitable standard size metric cylinder.

(b) Calculate the pump delivery required for both parts of the extend stroke.

Answer 1

Total thrust $F= 2.5 T = 24516 N$

maximum pressure $p = 200 bar = 2 0 \frac{N}{m^2}$

$A = \frac{\pi}{4} d^2 = \frac{24516}{20}=d=39.50$ mm

Piston velocity during extension stroke

$P_E = \frac{Q}{A_p}=\frac{200}{\frac{\pi}{4}39.50^2}=0.1632 \frac{m}{s}$