Analysys and Validation of Reciprocating Screw and Coupling of Injection Molding Machine

Transcription

1 ISSN Volume, Issue 11 Novemer 017 Analysys an Valiation of Reciprocating Screw an Coupling of Injection Moling Machine Mr.Venugopal P. Kulkarni 1, Mr. Amit Belvekar-Patil, Ahimanyu Changue 3 1 Asst.Professor,Department of Mechanical Engineering, MITAOE, Pune, Inia. Asst.Professor,Department of Mechanical Engineering, MITAOE, Pune, Inia. 3Asst.Professor,Department of Mechanical Engineering, MITAOE, Pune, Inia. Astract The injection moling machine melts an plasticizes the moling material insie the heating arrel an injects this into the mol tool to create the mole prouct y soliifying insie it. Reciprocating screw acts like a shaft in this machine an plays vital role in hanling of molten material. Prolem face in the inustry is the wearing of threas ue to effect of high temperature of molten materials like nylon, low ensity polypropylene, polystyrene, PVC etc. Prouction is struck ecause of failure of the screw leaing to loss of time an money. This work involves moelling of the components of machine with imensions, assemling of those components an then simulating the whole assemly for rotation of the screw using moelling software CATIA VR0. The thermal an stress analysis rotating screw is one using software ANSYS 1.. After otaining the results, new material will e suggeste for screw an arrel as a permanent solution for new machines which will come in the market. For existing machines, esign an analysis will e one for coupling so that coupling will e mae as a weaker part in the rotating system an which will fail efore failure of screw which will save large amount of cost an time. Keywors Injection moling machine, Reciprocating screw. I. INTRODUCTION The injection machine melts an plasticizes the moling material insie the heating cyliner. It further injects this into the mol tool to create the mole prouct y soliifying insie it. The injection machine is constructe of a mol clamping evice that opens an closes the mol tool, an evice that plasticize an inject the moling material. Injections moling machines can e classifie ase on the arrangements as given elow. (1) Horizontal injection machine : oth mol clamping evice an injection evice compoune horizontally () Vertical injection machine : oth mol clamping evice an injection evice compoune vertically (3) Two-color injection machine () Rotary injection machine () Low foam injection machine () Multi material injection machine (7) Sanwich injection machine. Injection moling is the most commonly use manufacturing process for the farication of plastic parts. A wie variety of proucts are manufacture using injection moling machine, such as plastics housings, consumer electronics, an meical evices Incluing valves & syringes which vary greatly in their size, complexity an application. The injection moling process requires the use of an injection moling machine, raw plastic material, an a mol. The plastic is melte in the injection moling machine an then injecte into the mol, where it cools an soliifies into the final part. Fig.1 : Injection moling machine 109 Mr.Venugopal P. Kulkarni, Mr. Amit Belvekar-Patil, Ahimanyu Changue

2 ISSN Volume, Issue 11 Novemer 017 Fig.1 shows the generalize iagram of Injection moling machine.the arrel contains the mechanism for heating an injecting the material into the mol. This mechanism is run y a reciprocating screw. Reciprocating screw avances the material forwar y either a hyraulic or electric motor. During this process the material is melte y heat & pressure. The material enters into the grooves of the screw. The screw completes the shot volume & returns to reverse position that is as the screw moves ack, plastic moves forwar. II. FAILURE OF THE RECIPROCATING SCREW Barrel of the Injection moling machine is surroune y numer of heating elements. As this heating element fails, the temperature of the molten material will e ecrease which turns to soliification. This increases the stresses on the reciprocating screw which results into the failure of the shaft. Sometimes many times it is oserve that shaft fails though there is no failure of heating elements. This is frequent prolem oserve in the plastic inustry. Cost of the reciprocating screw is high an also the time require replacing the shaft with newer one takes long time which is aout to working ays. This large loss of time an money leas to very high economical loss for inustry ue to struck of the prouction. Fig. refers to the photograph of roken reciprocating screw. Fig.: Photograph of faile reciprocating screw. The long term solution for aove prolem inclues reesign of reciprocating screw with new material. But the machines which are in running conition nees some immeiate remey y which there will e minimum loss of time an money after the failure of reciprocating screw. This temporary an immeiate remey inclues reesigning the coupling of the machine which connects river an screw. This coupling esign shoul e such that the coupling will e weaker part in the system. Before the stress limit reaches the reaking point of the reciprocating screw, coupling shoul reak which will save the reciprocating screw. The cost of coupling is very negligile compare to the reciprocating screw. Also time require to mount the new coupling is 3 hours which is negligile. This solution will very much economical for current running injection moling machines. This paper is aout the FEM analysis of reciprocating screw an coupling an then verifying the results of oth to verify the iea of reaking the coupling to protect the high values reciprocating screw. III. PAST RESEARCH WORK Y. Bereauxrecommene a moel of a single-screw extruer or the metering time of an injection moling machine for a given screw geometry, set of processing conitions an polymeric material is important oth for practical an esigning purposes. The moel is ase on viewing the entire screw as a pump, conveying a soli an a molten fraction.the moel also shows that the screw geometry is the mostimportant parameter, then polymer properties anprocessing conitions. P. Boey says that Glass-fille polymers areknown to prouce consierale wear on the arrels an screws of injection mouling machines. A few moel tests with the triological conitions in the injection mouling machine has evelope to fin the suitale coatings an treatments to the wear. Mae a new wear tester that evelope to simulate more closely the wear which occurs insie the arrel of an injection mouling machine. IV. FEM ANALYSIS FEM analysis inclues following steps. A. Making CAD moel of reciprocating screw B. Stress analysis of reciprocating screw at increase temperature C. Design of suitale coupling D. Making CAD moel of coupling E. Stress analysis of coupling 109 Mr.Venugopal P. Kulkarni, Mr. Amit Belvekar-Patil, Ahimanyu Changue

3 ISSN Volume, Issue 11 Novemer 017 A. Making of CAD moel of reciprocating screw Computer aie moel of reciprocating screw is create using suitale esign software CATIA V. Dimensions are as actually measure on site. Fig.3 is the CAD moel of reciprocating screw. Length of the hu ( l h ). l h mm.mm Pitch circle iameter for the olts (D). D mm 111mm Fig.3: CAD moel of reciprocating screw B. Stress analysis of reciprocating screw at increase temperature Stress analysis of the reciprocating screw is carrie out with analysis software ANSYS 1.. Analysis is one y using tetraheron type meshing an ounary conitions as one sie fixe at temperature more than 300ºC. Torque applie to the shaft is equal to Nmm which is ase on motor power kw availale on site. Material of the screw is EN1B (SAE100).Maximum stress value to e note from the analysis. Fig. refers to stress analysis of reciprocating screw. Thickness of the flange (t). t mm 18.mm Thickness of the protecting rim ( t 1 ). t mm 9.mm Diameter of spigot an recess ( r ). r mm.7mm Fig. : Equivalent Stresses of reciprocating screw (MPa) C. Design of coupling Step I- Shaft iameter ( ) The iameter of the shaft on which reciprocating screw is mounte is equal to 37 mm. 37mm Step II- Flange imensions Outsie iameter of the hu ( h ). h mm 7mm Outsie iameter of the flange ( D o ). D o t ) ( 1 ( 37 9.)mm 1.mm Step III Torsional shear stresses Torque (T ) transmitte. Take the motor power P as 11.18kW an numer of revolutions N of the reciprocating screw as 9 rpm. P 010 T N Nmm 109 Mr.Venugopal P. Kulkarni, Mr. Amit Belvekar-Patil, Ahimanyu Changue

4 ISSN Volume, Issue 11 Novemer 017 Polar moment of inertia (J ) for the coupling. h ( J mm (7 37 ) 3 ) Shear stress ( ) on reciprocating screw. h T. T. r J J N/mm 8T DN p mm D. Making CAD moel coupling Computer aie moel of reciprocating screw is create using suitale esign software CATIA V. Dimensions are as per the esign of coupling step mentione earlier. Fig. refers to CAD moel of coupling. Step IV- Diameter of olts For shaft iameter less than 0 mm,the numer of olts N recommene are 3. N 3 Material of the olt as C-. Yiel strength Syt for this material is 380 N/mm. Hence permissile shear stress p S yt 3 1.7N/mm. Diameter of the olt ( ). of the olts is equal to Fig. : CAD moel of the coupling E. Stress analysis of coupling Stress analysis of the coupling is carrie out with analysis software ANSYS 1.. Analysis is one y using tetraheron type meshing Torque applie to the coupling is equal to Nmm which is ase on motor power 11.18kW availale on site. Material of the coupling is consiere as Mil Steel variant. Maximum stress value note from the analysis. Fig. refers to stress analysis of coupling. TABLE I Sr. No. Part V. RESULT Maximum Stress inuce (MPa) Fig. : Equivalent stress analysis of coupling 1 Screw 18.0 Coupling Mr.Venugopal P. Kulkarni, Mr. Amit Belvekar-Patil, Ahimanyu Changue

5 ISSN Volume, Issue 11 Novemer 017 VI. CONCLUSIONS From the result it is clear that the stresses inuce in the coupling are more when we make the coupling of weaker material than that of reciprocating screw. In case of the failure of heaters, there is large chance of reaking of the reciprocating screw. If coupling of weaker material as suggeste here mounte in the system, an then it can protect the reciprocating screw which leas to avoi high wastage of time an money. Definitely this is short term solution which is applicale for the currently running machines in the plastic inustry. For long term solution, the work is eing one on reciprocating screw esign improvement. ACKNOWLEDGMENT The author woul like thank Prof.ShaileshPimpale for his valuale review, all time support an continuous encouragement. The author woul like to thank S Square Inustries Lt., Pune for giving a chance to make a research over a suject an permitting to pulish the work. REFERENCES [1] A simple moel of throughput an pressureevelopment for single screw -Y. Bereaux, J.-Y.Charmeau, M. Mogueetc (009) Journal of material processing technology Num.09, pp [] The effect of temperature on the arasive wear of coatings an hyri surface treatments for injectionmouling machines -P. Boey, W. Ho, S.J. Bull,University of Newcastle, UK ScienceDirect, vol. 8,Issues1-, Jan.00. [3] Soohong Kim, Ching-Shin Shiau, Byung H. Kim &Donggang Yao -Injection Moling Nanoscale Features with the Ai of Inuction Heating(007), Polymer-Plastics Technology an Engineering, :11, [] Shuiao Cui, Zhigao Huang & Yun Zhang - System Design an Implementation of an Integrate CAE System for Injection Moling,. [] A B M Saifullah, S.H. Masoo an Igor Sarski - New Cooling Channel Design for Injection Mouling. Proceeings of the Worl Congress onengineering 009 Vol I WCE 009, July 1-3, 009, Lonon, U.K. [] g_process.html [7] Mr.Venugopal P. Kulkarni, Mr. Amit Belvekar-Patil, Ahimanyu Changue