Design and Construction of a Universal Pipe-Bending Machine G.M. Ngala*, M.B. Oumarou. and A.B. Muhammad

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1 University of Maiuguri Annals of Borno Volume XXVI, June 016 Design an Construction of a Universal Pipe-Bening Machine G.M. Ngala*, M.B. Oumarou. an A.B. Muhamma Department of Mechanical Engineering, University of Maiuguri, P.M.B. 1069, Maiuguri - Nigeria garba.ngala68@gmail.com; ABSTRACT A universal pipe bening machine has been successfully esigne an constructe using locally available materials. The manually operate machine is portable an can be mounte in a workshop, as part of prouction machineries or in construction site to ai pipes, ros an angle irons bening operations so as to enhance prouctivity an early completion of projects. The mechanical efficiency of this machine base on the mechanical avantage an velocity ratio was etermine to be 80%. Due to its cost of prouction, prouction efficiency an simplicity of operation, the machine is foun to be quite suitable for use in eveloping countries. Keywors: Design, Universal bening, Machine, Efficiency INTRODUCTION Most of the problems of leakages on pipes conveying portable omestic water supply to an within builings occur as a result of poor quality joints, especially elbow joints that warrant miss-fitting or misalignment of the pipes, hence causing a substantial quantity of our scarce water to effortlessly escape to the surrouning environment through the gaps. The escape water frequently accumulates aroun the builings, serving as a breeing groun for mosquitoes an/or emitting offensive smell, thus causing serious health hazars to the inhabitants (Cheremisinoff an Young, 1976). An alternative way of ealing with such plumbing problems is to avoi the use of elbow joints, which hitherto ominates joining of two pipes at right angles (90 ). It is therefore necessary to employ the use of machinery that prouces such bens with improve efficiency an cost effectiveness. The universal pipe bening machine, which is preferre to serve this purpose in this stuy, is extremely use for the bening of metal pipes an structural reinforcements of ifferent iameters. It is a small manually-operate machine that can be use to ben common pipes mae from steel, brass, copper, etc. The first mechanical bening machine was constructe by Frerick Stout aroun 800 BC (Michael, 1986). Over the years, several inventions an moifications have occurre. In 1900 the bening machine has alreay reache a high level of evelopment an was in wie use in America an continental machine shops. By 195 the work of Fre Holz an A.L. Deleew ha le to the construction of heavy bening machines having stan knees, interchangeable Annals of Borno, Volume XXVI, 016 Page

2 frames an sizes. One of the most important avances in the bening machine at this time was the steay spee of prouction (Eugene an Theoore, 1997). Toay, various types of specialize bening machines exist; notably, the moifications of the manual type to hyraulic an pneumatically operate machines, which mae possible the wie use of precision ies for high precision work an efficient prouctivity even by relatively unskille labour. Drop forging for automobile inustry were built for For as early as 191. The work of people like Sol Einstein, Hazelton an Deleew le to the evelopment of several other beners like the ram bener, mechanical power presses, roll beners an rotary beners (Eugene an Theoore, 1997).However, it is regrettable to observe that most of these machines are heavy an expensive. Therefore, the aim of this stuy is to esign an construct an afforable an portable single pipe bening machine from locally available materials. The esign incorporates a provision for its installation in workshop as a prouction tool as well as a emonstration evice for stuents, thus also serving the nees for both teaching an research. Description of machine an principles of operation As shown in fig. 1, the universal pipe bening machine is mae of three major parts. The stan() which is mae of a cylinrical pipe of iameter 10mm wele between two mil steel plates of 440mm x 60mm x 6mm(11). The pipe is of height 900mm. The stan carries the bulk of the machine (the fixe frame an the swinging frame), an it is the meium that gives stability to the machine by bolting it to the workshop floor. The fixe frame (or the main frame)(1), consists of two mil steel bars of 750mm x 50mm x 6mm, each of them is ben to 45 o at 40mm from the en. The two bars contain ten rille holes on them; the first is the biggest hole of mm which contains the fulcrum pin that hols the bening ie. The other two holes at the en are for bolts an nuts an the secon hole after that is for a spacer(5) separating the two frames an aing strength to the frame. The swinging frame (swinging arm)(9) resembles the fixe arm, except that it hols the hanle, an the bening process is achieve by the movement of this arm. Another ifference is that the number of spacers is one more than that the fixe arm. The secon spacer calle the roller () is the main component that carries out the bening process. An effort of 00N is applie at the hanle which is converte into aroun 4000N at the roller. The bening process is carrie out between the fixe frame, swinging frame an a forging ie of suitable iameter. The pipe to be bent is place between these three elements an an effort of 0 N applie at the swinging arm via the hanle, results into bening process at the fulcrum where a 00N force is now converte into 700N an the bening process is carrie out up to the require angle. Annals of Borno, Volume XXVI, 016 Page 4

3 Ngala et al.; Design an Construction of a Universal Pipe Bening Machine Fig. 1; Isometric View of Universal Pipe bening machine MATERIALS AND METHODS The general properties of any material forming an engineering component epens on its chemical make-up, how it is buil up from atoms an molecules into crystals, grains an soli material, an on the manufacturing processes an treatments use to prouce its final form an conition. When a material is selecte for a particular engineering situation, a variety of these properties have to be consiere incluing strength, machinability, corrosion resistance, electrical characteristics, thermal conuctivity, melting point, etc. Often, however, these requirements have to be balance; one against the other an the choice of material therefore usually involve a compromise (Hannah an Hillier, 1995). Basic requirements for materials selection for the machine components were consiere in this stuy. Even though, the final choice usually involves a compromise, the requirements can be broaly classifie as, service, fabrication an economic requirements (Khurmi an Gupta, 1997). More than 90% of the materials use in the construction of this machine are mil steel. This is as a result of the compromise obtaine from the three lai own criteria.the machine consists of three major parts; stan, fixe arm an the swinging arm. Annals of Borno, Volume XXVI, 016 Page 5

4 Design consieration In orer to effect an acceptable esign, the question of workability, urability an reliability of the components constituting the bening machine must be given ue consieration. The workability of the bener is a question of proviing components, which perform in accorance with the esign specifications an integrating these components into an operational feasible unit. Durability ensures that the machine will continue to operate uring its esign life without material or component failure, while reliability ensures that the machine performs accoring to the esign requirements. Design Calculation Hanle Bolt Diameter In orer to etermine the iameter of the bolt that can withstan the loa of 00N, which is the stanar force, prouce by a normal average human being (Abbott, 1985), the torsion formula is use. Normally for a simple twisting moment T, on a soli circular shaft of iameter, the maximum shearing stress is given by S s max (1)(Hall et al,; 198) Let s assume that failure is base on maximum shear theory; the maximum shear stress must not excee the allowable shear stress Ssall For mil steel Ss = 40MN/m (Khurmi an Gupta, 1997) Annals of Borno, Volume XXVI, 016 Page 6

5 Ngala et al.; Design an Construction of a Universal Pipe Bening Machine F C E 100mm L1 F1 M1 G G 5 700mm L 700mm 800mm D B 60mm 5 RB Fig.a Schematic iagram A Fig.b. Equivalent system iagram A S sall =16 MN/m, where.5 is the factor of safety..5 Torque T is calculate to be 0 Nm, since the length of the hanle CG is 0.1m an perpenicular force applie is 00 N(Fig. a). Hence the Torque is ivie by two because there are two bolts holing the hanle. T=15 Nm. 8. 5mm Nearest stanar size of 10mm iameter bolt is chosen. Bening Die Pin Diameter Clockwise moment = Anticlockwise moment F1L +M1 = RB X 0.06Cos85 o (Fig. b) 00 X = RB X 0.06 X RB = 46 kn The pin is uner the reaction of 46kN force Shearing will occur at two points along the pin. Therefore, RB being 46kN is ivie by to give Annals of Borno, Volume XXVI, 016 Page 7

6 46 F B kn F () A where A is the cross sectional area 4FB S sall mm Nearest stanar size of 16mm iameter bolt is use. Forging Die Pin Diameter Using equation, An torque, T = 00 x 0.8 =40 Nm 16MN / m 0.79mm Nearest stanar size of mm iameter ro is use. Die raius In etermining the former raius (min) for bening of a given pipe, a simple practical formula is use. The minimum raius necessary is given by (Spotts, 1985). Rmin D p. (4) Where Rmin = minimum raius of former Dp = Diameter of pipe to be ben mm For a,, 1 pipe, Rmin =DP Annals of Borno, Volume XXVI, 016 Page 8

7 Ngala et al.; Design an Construction of a Universal Pipe Bening Machine For,, R pipe 4 R min min mm Backing Die Pin Diameter Since the backing pin ro is uner irect shearing stress an the shear occurs at two points, equation can be use to etermine the backing ie iameter, thus F F S saa 14.6mm Nearest stanar size of 16mm iameter is selecte. Bolt Diameters for Fixe Arm Support Since there are four bolts connecting the fixe arm, connecting arm an the stan pipe, only the first two that are uner the same action are consiere. The torque transferre to the stan pipe is 0.79Nm. The torque, T for each bolt will then be Nm Diameter of bolt is etermine using equation that is 8. mm Nearest stanar size of 10mm iameter bolt is use. The other two bolts connecting the arm an the table are uner the turning force of 15.7Nm. Each bolt is then uner the torque of 7.69Nm. Using equation 6. 6mm Nearest stanar size of 10mm iameter bolt is use. Efficiency of the Machine Principle of ynamics is use to etermine the mechanical efficiency (Abbott, 1985). mechanical.. avantage mechanical.. efficiency velocity.. ratio Annals of Borno, Volume XXVI, 016 Page 9

8 Loa M. A Effort Effort = 00N (Abbot) Loa = 700N 4000N.(Determine using the principle of moment on the swinging arm) M. A R Dis tan ce.. move.. by.. effort Velocity ratio = 60 istan ce.. move.. by.. loa r R 1 V. R r 0.06 V. R M. A % 80% V. R m Machine Construction an Assembly Each component of this machine was fabricate base on the results obtaine from the esign calculations. The main frame was constructe using two mil steel bars of 70mm x 50mm x 6mm, they are cut to size using power saw an then bent to 45 o at 80mm an 40mm from the other en using True-fol bening machine. Ten holes are rille on each arm. Firstly, a mm iameter hole for the fulcrum pin, followe by seven holes of 18mm iameter for bening ie pin an finally two other holes of 16.5mm iameter for bolts an nuts.the swinging frame or arm has the same manufacturing process with the fixe frame; the only ifference being the iameter of the last two holes, i.e., 14mm. The stan was mae of two plates of 440mm x 60mm x 6mm wele to a cylinrical hallow pipe of height 900mm, external iameter of 17mm an internal iameter of 98mm. Four holes of 16.5mm iameter were rille on the bottom plate an three on the top plate for installation an assembly, respectively.the bening roller was mae by rilling mil steel ro of 4mm external iameter x 155mm height with an 18mm rill bit on a Raial rilling machine. The backing ie was mae by cutting a rectangular block of 50mm x 50mm with a height of 10mm by a power saw an then rilling an offset hole of 18mm iameter on the block to accommoate the ajustable backing ie pin.the main frame spacer has the same manufacturing process with the roller except for the ifference in height which is 185mm.The fulcrum pin, bening ie pin, backing ie pin are all prouce using the same manufacturing process. They were turne on a Lathe machine to Annals of Borno, Volume XXVI, 016 Page 40 60

9 Ngala et al.; Design an Construction of a Universal Pipe Bening Machine their require respective iameters. The hanle was mae of a steel pipe rille at two points for coupling with the swinging arm. It also has a provision for extension into which a mil steel bar of varying length can be inserte. This is to provie higher mechanical avantage an subsequently higher efficiency. The stanar bolts an nuts were purchase from the market. The machine is then assemble by first bolting the stan to the workshop floor, an then coupling the two frames separately before bringing them together. The fixe frame comprising of the two bars space apart by the spacer an carrying the backing ie are couple to the stan by means of bolts an nuts. The swinging arm is also assemble separately with its hanle, spacer an bening ie. Then, this assembly is finally couple to the fixe frame by means of a fulcrum pin which also hols the forging ie.the cost of manufacture of this machine is aroun N0, Testing of machine The machine is teste on various types of pipes (Copper, Brass an Steel) of ifferent iameters. Reinforcement ros are also use on the test an it was generally a success. Square pipes can also be bent using another set of ies. CONCLUSION The esign an construction of a universal pipe-bening machine using common grae of mil steel was successfully carrie out using simple fabrication techniques. The machine has an efficiency of about 80%. It is foun to be suitable an afforable for eveloping countries with a total materials cost of N90,000:00. By simply changing the ies, the machine attains a new capability of bening other materials of ifferent geometry either than the pipes. Even though the machine is versatile in its operation, it shoul be note that separate bening formers have to be built to suit each particular iameter as require. Annals of Borno, Volume XXVI, 016 Page 41

10 REFERENCES Abbot,A.F. (1985). Orinary level Physics Secon Eition, Macmillan Press Lt. Lonon. Cheremisinoff, P.N. an Young, A.R. (1976). Pollution Engineering Hanbook secon eition. ann arbor science publishers Inc. p Eugene, A.A an Theoore, B. (1997) Marks Stanar hanbook for Mechanical Engineers 10 th Eition, p18-, an Hall, A.S., Holowenko, A.R. an Laughtin, H.G. (198). Theory an Practice of Machine Design; Schaums outline series McGraw-Hill Book Company. New York. Hannah, J. an Hillier, M.J. (1995). Applie Mechanics, Thir Eition, Longman, Printe in Malaysia. Pp 448. Khurmi,R.S. an Gupta,J.K.(1997) A Textbook of Machine Design, Eurasia publishing house limite. New Delhi, Inia. Micheal Walsby (1986). How to Make Pipe Bening Machine. Intermeiate technology publication. New York, U.S.A. Spotts, M.F. (1985).Design of Machine Elements. Prentice- hall Inc. Englewoo cliffs. New Jersey. U.S.A. Annals of Borno, Volume XXVI, 016 Page 4