Posted: March 5th, 2016

A simple small moulding machine has three pneumatic linear actuators 1. Pneumatic Linear Actuator (Pneumatic Cylinder) opening and closing the mould 2. Pneumatic Linear Actuator (Pneumatic Cylinder) moving the barrel forward against the mould and back away from the mould 3. Pneumatic Linear Actuator (Pneumatic Cylinder) moving forward injecting polymer and returning (refilling for the next shot). The process has the following constraints When the mould is closed the barrel may move forward and back, when the barrel is forward the injector may be moved forward and back, the injector must be back before the barrel can move, the barrel must be back for the mould to open and close. When the mould is opened the part can be removed. Both the time the mould is closed and the time injecting linear actuator is forward should be adjustable. Section A  Investigate Timing Diagrams.  Analyse with the use of a timing diagram the process. 10  Define the inputs and outputs required for a control system. 10 Section B Either  Develop a suitable PLC or other electrical control circuit to control the above with where all end conditions are fed back using limit switches and the inject forward and mould close has a timer control. 30 And  Devise a pneumatic circuit to complete the above operation. 30 (Fluidsim may be used for this)  A written explanation of the solution 10 Or  Devise a purely pneumatic circuit to complete the above operation. (Fluidsim may be used for this) 50  A written explanation of the solution 20 Section C For Either Solution  Advise how speed control on all linear actuators would be 10 achieved.

A simple small moulding machine has three pneumatic linear actuators
1. Pneumatic Linear Actuator (Pneumatic Cylinder) opening and closing the mould
2. Pneumatic Linear Actuator (Pneumatic Cylinder) moving the barrel forward against the mould and back away from the mould
3. Pneumatic Linear Actuator (Pneumatic Cylinder) moving forward injecting polymer and returning (refilling for the next shot).
The process has the following constraints
When the mould is closed the barrel may move forward and back, when the barrel is forward the injector may be moved forward and back, the injector must be back before the barrel can move, the barrel must be back for the mould to open and close. When the mould is opened the part can be removed.
Both the time the mould is closed and the time injecting linear actuator is forward should be adjustable.
Section A
 Investigate Timing Diagrams.
 Analyse with the use of a timing diagram the process. 10
 Define the inputs and outputs required for a control system. 10
Section B
Either
 Develop a suitable PLC or other electrical control circuit to
control the above with where all end conditions are fed back
using limit switches and the inject forward and mould close
has a timer control. 30
And
 Devise a pneumatic circuit to complete the above operation. 30
(Fluidsim may be used for this)
 A written explanation of the solution 10
Or
 Devise a purely pneumatic circuit to complete the above
operation. (Fluidsim may be used for this) 50
 A written explanation of the solution 20
Section C
For Either Solution
 Advise how speed control on all linear actuators would be 10
achieved.