PneumobotSprue Picker Robot

Contents
•Problem Statement
•Plastic Injection moulding
•Robotics
•Automation 2012 visit & IATF 2013
•Design and analysis
•Pneumatics and electricals
•Fabrication

Problem Statement1. To Enhance the productivity in IMM industry using automation and resolve issues regarding workers. 2. To perform pick and place operation within 8 seconds from IMM to Granulator.

Purpose of Project
1.Consistency
2.Fast Cycle time
3.Less Labor Cost
4.Product Hygiene
5.Safety Issue
6.2ndlevel Automation
7.Continuous Operation
8.Productivity

Abstract
•Electro-pneumatic robot for automation in plastic IMM having mechanical gripper to remove sprue (waste component) from the mold and placing it into Granulator.
•A linear and rotary pneumatic actuator will be used to give required motions.
•Mitre Bevel gear to transmit power and torque. Linear nylon made slider for easy sliding motion
.

Methodology
1.Robot models and IMM study
2.Exhibitions
3.Industry survey
4.Brain storming
5.Pneumatics and Electricals.
6.Design and material selection
7.Analysis
8.Design review and synthesis
9.Fabrication
10.Testing and results

Process flow in IMM :

Parts of Horizontal Injection moulding machine
*
Schematic of thermoplastic Injection molding machine

Arburg machine specifications :
Clamp Tonnage / Machine
Tie Bars ClearanceHxV(mm)
Injection WeightPS. g (oz)
Min -Max Mould Height. (mm)
Opening Stroke Max (mm)
25 Arburg
221
32 (1.13)
150 -300
200
40 Kawaguchi
275 x 245
73 (2.57)
150 -250
230
*55 Arburg
320 x 320
78 (2.5)
min 225
350
*88 Arburg
370 x 370
89 (3.4)
min 200
450
*110 Arburg
420 x 420
153 (5.9)
min 250
575
125 Kawaguchi
435 x 375
226 (7.97)
180 -400
355
140 Kawaguchi
435 x 375
260 (9.17)
180 -400
355
175 Kawaguchi
445 x 445
372 (13.1)
250 -450
400
*220 Sumitomo
610 x 560
532 (18.8)
250 -580
510
265 Kawaguchi
550 x 550
649 (22.9)
200 -550
500
*280 Sumitomo
685 x 635
733 (25.9)
300 -620
580
300 Dongshin
685 x 580
970 (34.1)
300 -680
600

Component with sprue
Component without sprue

Proposed designs
1.Guide way cartesian model
2.Articulated type (scara,revolute) 3. Cartesian type
4.Swing arm type (vertical) 5. Swing arm type (horizontal)

Types of products :

Robot Applications inside & outside the Mold
Two Plate Mold
Sprue Picking Only
Sprue and Parts RemovalPart RemovalSprue Picking with Part Dropping
Sprue Picking with products connected
Part removal with the sprue or without the sprue
Simple OperationTaking out the Sprue from the mold and dropping it. ( Inside of the mold, Conveyor , Box )
Remove Parts, 90deg Rotation and Placing the parts ( Conveyor, Box)

Mounting Position of Robot
Pick Operation
Arm : Double arm or Single Arm
Descent Position : Nozzle or Clamp
Motion Style : U or L
Operation : Vacuum, Chuck, Gripper

Robot case-study models :
1.ArticRSL
2.YushinHop 5
3.Sailor RX-8
4.Wittmann Battlefeld w702
5.Sepro S3 picker
6.Arburg integral picker
7. Phoenix

Complete Process Chart Yes No Raw material (RM) for coloring and mixing Arrival of Raw materials & mould Mould on moulding machine using hoist RM feed to the Hopper Moulded components for finishing Sprue & defectives to granulator Component package and storage Dispatch of Component Start End Is product defective?

Catia model of Picker machine on fixed platten
Drafted image

Cylinder selectionCylinder selection : Cylinder selection from Janatics Pneumatics catalogue through requirement of std stroke, bore and force. 3 A52 magentic cylinders and 1 A03 series male threaded cylinder for gripper. Dimensions and mechanisms of robot were finalized from cylinder selected.
•Swing Cylinder Stroke 50mm ,Diameter 25mm
•Kick Cylinder stroke 80mm ,Diameter 20mm
•Vertical cylinder stroke 160mm ,diameter 16mm
•Gripper cylinder stroke 20mm, diameter 16 mm.

Mechanisms
1.Quarter turn pulley
2.Power screw
3.Electric motor
4.Rack and pinion
5.Pneumatic 4 piston actuator
6.Spiral Bevel gear pair

Design considerations :
We have used factor of safety of above 3 everywhere except in caseof gear we have fos = 2.4Our design is safe at 8 bar pressure. and gear pair fos is 1.2 at 8 bars. Solenoid valves can operate at max of 8 bar pressureAll other pneumatic component can sustain 10 bar pressure.

Design innovationsMitre bevel gear eliminated the need for wrist rotation of gripper plus reduced 1 movement of vertical cylinder. Arc bracket provides rotation on either side. Self made slider from nylon on Aluminium was made. Gripper was developed from compact cylinder.

Analytical design and analysisOur calculations predict that each cylinder can retract or extend in 0.2 seconds so we retrict ourself to max. of 4 to 6 bar pressure operation. As cycle is to be completed in 8 seconds, 4 bar pressure is sufficient. We designed Mitre bevel gear from Design data book taking cylinder specs into account. From gear pair , Shaft was designed. Bearing selection was done thenColumn was checked for buckling analysis. Swivel motion arc bracket was made. Cantilever beam analysis for carriage ,then Mountings plus sliding chuck was designed. Strong foundation design and guideways for vertical cylinder were provided at last.

Design of assembly in CATIAPart drawing was done in CATIA V5 and then assembly was done. Material was applied appropriately and CG ,weight ,MI were calculated then. Drafting was done for mfg drawings to workshops.

Material selection :
1.Cast IronIt has good damping property and less density than steel but costly and not readilyavailable. Density= 7250 kg/m^3.2. Mild SteelIt has compartively less damping but good welding characteristics and cheap plus readily available. Density= 7850 kg/m^33. AluminiumLight weight with hardness and stiffness. Easy riveting possible. Density = 2710 kg/m^3 4. NylonFor easy sliding of carriage , nylon or teflon was considered.

Ansys analysis
Critical components like horizontal shaft, arc bracket , base plate were examined for static and dynamic failure.
Fos was safe for design made.

Pneumatic circuit concept
1.Push button operated
2.Interlocking circuit using limit switch operation
3.Electro-pneumatic circuit using relays,reeds and solenoids.
4.Micro-controller based.
5.PLC based.

Pneumatic circuit working

Automation Studio 5.0Pure pneumatic circuit was made in this software but electro pneumatic circuit was just developed but not simulated. Fluidsim and autosim (SMC) softwares were tried out.

Electro-pneumatic circuit :
The sensing time of reed switch is 1 millisecond.
Reeds operate at 24 V DC
Solenoid valves operate at 24 V DC with 104 mA current.
As relay logic and logic gates could not be built , we choose controller.
So A micro controller 8052 was used taking sensors as inputs (8) and solenoids as output (8) . Reset function was provided in case of sudden stops.
C programming successfully implemented the required logic on controller.

Gripper
1.Mechanical 2 finger gripper
2.Vaccum gripper2 finger gripper had to be imported hence made a compact gripper from small double acting cylinder having one fixed jaw and other movable.

Habonim 4 piston actuator :

Robot Specifications
1.Payload : ½ kg
2. Weight : 22.4 kg
3. Cost : 51,200 uptil now
4. Control method : Micro controller
5. Material : Mild steel for foundation, Aluminium for manipulator
6. Configuration : Semi-cylindrical (swing arm)
7. DOFs : 4 (3 cylinder + 1 gripper)
8. Actuator : Mitre bevel gear rotation using swing cylinder
9. Kick stroke : Linear nylon guide rail.
10. Vertical stroke : Gripper with guide way
11.M/c tonnage : 30 to 55 tons
12. Power supply : 24 V DC ,1 A
13. Air consumption :
14. Swing angle : 50 to 90 deg both sides.
15 .Max pressure: 6 bar
16. Working pressure: 2 to 4 bar
17. Overall cycle time : within 8 secs.

BOM 1 out of 4 bills
Sr. no
Model no.
Specification /product
Qty
Cost
Total
1
A52020080O
DA 20 x 80 Cyl.(Mag) Basic
1
1243
1243
2
A52025080O
DA 25 x 50 Cyl.(Mag) Basic
1
1323
1323
3
A52016160O
DA 16 x 160 Cyl.(Mag) Basic
1
1176
1176
4
DS254SS60-W
1/8 -5/2,24V DC Double Sol. valve
4
2030
8120
5
GR5105006
Flow control valve 1/8 x Dia 6
6
224
1344
6
WP2210650
Male elbow Dia 6 x 1/8
8
43
344
7
MS022
DOUBLE FOOT MOUNTING (DIA 20,DIA 25)
1
234
234
8
AA022
CLEVIS FOOT BRACKET (DIA 20,DIA 25)
1
148
148
9
AP010
ROD END SPHERICAL EYE (DIA 25,DIA 32)
2
560
1120
10
AP008
ROD END SPHERICAL EYE (DIA 20)
1
511
511
11
AM1016
Reed switch with clamp (A52016)
2
451
902
12
AM1020
Reed switch with clamp (A52020)
2
451
902
13
AM1025
Reed switch with clamp (A52025)
2
451
902
14
FRCLM146234/W
FRCLM-3/8(40Micron,10bar)with Wall mounting brack
1
2649
2649
15
WP2110851
Male connector Dia8x 1/4
2
36
72
16
M0030104
Manifold (4 Valves) DS2-1/8,5/2,5/3
1
1355
1355
17
ASC0161
Silencer (Conical-1/4)
2
83
166
18
WP2110852
Male connector Dia8x3/8
1
41
41
19
A2G02
Pressure gauge(0-10bar)R1/8,Dia 40
1
171
171
20
WH00B08
TUBE(PU) OD8 (Blue)
2
56
112
21
WH00B06
TUBE(PU) OD6 (Blue)
8
31
248
22
Parallel Gripper (10/ 16 dia)
1
0
23
Reed switch for parallel gripper
2
0
24
WC1
Tube cutter
1
135
135
Total
23218

Motion sequence of Pneumobot:
1. vertical arm descend Cylinder A+
2. strip forward Cylinder B+
3. grip on / vaccum on Gripper C+
4. strip backwardCylinder B-
5. vertical arm retract Cylinder A-
6. swing outward Cylinder D+
7. grip off /vaccum offGripper C-
8. swing inwardCylinder D-
We implemented the logic A+B+C+B-A-D+C-D-using relay(4 three pin & 4 five pin relay) along with 4 double solenoid valve and 8 reed switches(magnetic sensor).
Above sequence can be changed as required using micro-controller or PLC.
For interfacing with IMM , micro-controller or PLC is needed.

1.Milling
2.Boring
3.Tapping
4.Welding
5.Grinding
6.Drilling
7.Turning and Facing
8.Laser cutting
9.Hack saw cutting
10.Rivetting
11.Surface finishing
12.Grub holes
Fabrication operationMaterial was purchased from Bhosari. Manufacturing was done at Talwade,AkurdiFinal mfg and finishing was done at Nangergoan ,Lonavla

Final Assembly
All components were joint and made ready.
Piping was done properly along with sensor wiring connection through insulation casing.
Manifold and controller housing was done. Gauge and frc unit was interfaced then.

Thank You