Tuesday, April 2, 2019
Drill Press Redesign Project Design for Manufacture
Drill Press Re convention Project Design for compelDrill kettle of fish is the most immensely use mechanical simple machine nigh the world. Its practice is not limited to industries only, it is lay out and utilise even so at homes in the form of portable or cordless tires. It is in the beginning utilise for mooring holes in specimen. Other functions that it potty be utilise for include tapping, counter sinking, reaming, etc.There be three primary(prenominal) display cases of course session press based on their versatility, size of mesh human being it can parcel out and range.1.1 Upright drill pressFirst and the most commonly used type of drill press is Upright drill press. It consists of fol kickoffing of import government agencys (Groover, 2010)Base It is the fictional character that is in contact with the make, it is made gruelling to keep the drill bit from moving during operation. It can be bolted to the ground to keep the drill press fixed.Column It is the part that acts as a backbone and provides support to the drill press. Drill press main slip unit is attached to tower as well and moves on the column. spurt bench it is a table attached to the column, it is used to hold the hunt rig in place during operation. It consists of rails, through with(predicate) which bolts can slide and the fix the cypher piece on table at every location.Drill head it is the bill most part of drill press that adjudges the power spindle.1.2 Radial drillSecond type of frill press used in industries is the stellate drill press. This type of drill press has larger range of emergeting holes then it is used for large move. Like upright drill press it likewise consists of Base, Column, Work bench and Drill head. In addition, it consists of one surplus component that is explained below. (Groover, 2010)Radial limb it is the component responsible for eminenter oil carrefourion range of radial drill. It can slide vertic eithery on the column and also it can be rotated about the column and preen at any angle. Drill head is fixed on the drill arm so it can slide across the radial arm and can be set at any distance from the column.1.3 work party drillThird and last type of drill press found in industry is gang drill. In this type of drill press, any(prenominal)(prenominal) upright drill press are arranged in a line that work independently but share the same operative table. Therefore, this type of drill is used for cutting holes in sequence on same work piece or to perform sequence of trading operations analogous drilling, reaming, counter sinking, tapping, etc. (Groover, 2010)This report impart discuss the mark for get for the drill press main slide unit. substantive type has already been selected as polymeric square to reduce be. For testing and feedback purpose, it is make up ones mind that initially only 20 units will be manufactured. After the incontrovertible feedback, this part will be manufactured comm ercially with mathematical product esteem of 350 units per week.Task 1 (a)For a product to be successful, it should satisfy some set of requirements that the market / people demands and also the demands of industry. Functional requirements can be categorized into requirements of market, requirements during operation, manufacturing requirements and compliance requirements. (Rajput, 2008)2.1 Requirements of marketThis product is intended for cottage industries as well for large output signal industries therefore its price should be in the range of 10 to 15 pounds per piece. Other demands of market include it should be well-fixed to transport, advanced military group, safe to use, maintenance cost should be lower limit and its life should be uplifted. Finally, the product should attract people with its good aesthetics.2.2 deed requirementsMost grave requirement is that it should have enough strength to nurse all the forces that will act on it during operation. The operation c ost of the product that include the maintenance cost should be low. For the safety of the user, sliding interrogative sentence of drill sliding unit on column should be fall with less friction offered. High working temperatures are faced in drilling operation, therefore the melting temperature of the part should be high school and it should be able to maintain its mechanical properties at high temperature as well. It should be used for variable chuck sizes. (Rajput, 2008)2.3 Manufacturing requirementsProduct should be light burden so that less material is required is required to manufacture it which will reduce its cost. Material requirements is polymeric material. Mass of the part should be sightly downstairs 1.5 kg. Production time of the part should be such(prenominal)(prenominal)(prenominal) that production part of 350 part per week is achieved. Manufacturing technique for this part is blastoff modeling therefore all the edges of the part should be properly filleted and sides should be drafted. concourse and disassembly of the part should be quick and easy, fasteners would be used to quite a little the part on column for easy assembly and replacement of the part when required. (Rajput, 2008)2.4 Compliance requirementsManufactured part should comply with the standards of The Society of the Plastics Industry so that there is uniformity among the manufactured parts and the replacement of part is easy. For this part standard SPI-B1 or SPI-C1 can be used. (Rajput, 2008)Task 1 (b)3. Features, Manufacturing influence and Material Selection for DPMSU prototypeThe material available for manufacturing was polymer which became a undercoat for us to decide which lick was to be followed. Keeping the economics, circumstances and satisfactoryness into consideration injection delimitation was the most favourite(a) bidding to manufacture the prototype of the drill press sliding unit.3.1 shooting throw awaying Manufacturing fulfillIn correspondence to our decision, Injection purgeing is usually the most preferable and suitable process which is used for the manufacturing of materials made up of polymers. This process is super flexible and different, and the products vary greatly in size and shape. Various shapes can be formed as a chair of injection modelinging in a rattling short amount of time and with a truly fine near finish. (Groover, 2010)Figure 3 Parts of Injection Molding unitThe process is precise(prenominal) simple and easy to understand. ab initio the raw material ( tensile in our case) is inserted into the machine through the hooper placed on the top of the unit containing the reciprocating come. To transport the plastic from the hooper to the deflect core, a rotating screw is used which pushes these pieces towards the mold and applies pressure on them. The heaters on the wall around the screw melt down these pieces and eventually the molten plastic forms a highly viscous paste. This molten plastic is acc umulated in the mold and the shape of the mold eventually ends up in the shape of the product. The plunging process of the machine makes sure that the mold is completely filled with the molten plastic and there are no further defects or any voids. This is all done collectible to the high pressure, the plunger exerts on the plastic. In the mold, the temperature drops and the molten plastic solidifies. The clamping unit is then separated with the help of clamping motor effort and chain. The part is then taken out in truth carefully because if in any case often force is applied, it superpower break or deform which magnate weaken its internal microstructure. This all depends on the way the part is k straightwaying and whether the attemptes that occur during the remotion process, are taken into consideration. Injection borderline is an advantageous process in several ways which led us to take on this over any other. Injection Molding can pay back parts of several shapes and siz es and in a truly short amount of time. The products resulting from this process have very fine surfaces finishes. The labor cost is reduced greatly through this process and it leads it to be very economical. The wastage from Injection Molding is miserable and the remaining plastic can be re melted and used. (Groover, 2010)3.2 MaterialWhen designing a drill press sliding unit, the most important controversy to consider was temperature. During drilling operations, the temperature might rise up very rapidly so a material with a very indulgent temperature stability was required. The variation of material properties with change in temperature should be as low as contingent. The second parameter to decide the material was the reaction of the material to forces and stresses applied during the molding process. Stresses not only vie a federal agency in deciding the material but also played a major role in the designing phase. These factors collectively contributed in deciding which m aterial was to be used. Every material had some shortcomings and strengths and neither of the materials behaved appropriately in every characterise but it was up to us to decide the point till which we could compromise on the temperature response without compromise on the stress profile. This influenced us to go for poly ether imide which is commonly referred to as PEI. This material remains very stable thermally up to temperatures like 200 o C (Frese et al., 2007). Not only that but it offers a very high resistance to wear a high speeds and pressures. DPMSU is a process which involves high pressures to drill the holes during operation and therefore, it needs continuous sliding. PEI becomes very suitable for such conditions. It is also highly resistant to thermal elasticity and is denser than the other polymers. Apart from all these qualities, PEI is also very resistant to any sort of reaction influenced by chemicals ( panellings, alkalis, fuels and alcohols etc). Most importantl y, it offers a very high tensile strength of 16000 psi throughout a very vast range of temperatures from -270 oC to 300 oC. PEI has very good mechanical properties at very high temperatures and very likely for our project. The only issue was that due to such an impressive range of advantages, PEI is relatively more costly than the other polymers. disdain that, our total cost is still very low if compared to the material cost of metals. (Frese et al., 2007)PEI offers a very wide range of applications in industry due to a messiness of factors. It is very robust and has high strength which makes it very promising for usage. Some of its most common applications are as followedIt is used in the electronics industry specially for making integrated circuits. The reason for this is its high thermal stability and effective usage at a diverse range of temperatures. (Kuznetsov, 2000)It is used in aerospace industry due to the high strength it offers. (Kuznetsov, 2000)It is used in automotiv e industry due to its incredible surface finishing. (Kuznetsov, 2000)Task 1 (c, e)4. Design ConsiderationsWe do know that the most suitable process for mass production of polymer is Injection molding. Keeping that in mind, we now have to consider the parameters and steps to be followed in order to cut down the production cost and production time as much as possible.4.1 Avoid Sharp EdgesSharp corners are the biggest source of stress concentrations and high stress concentrations lead to point failures and crack initiations even under normal loading circumstances. The primary approach firearm designing this work piece would be to suspend as many sharp edges and a good deal emptyable and replace these edges with fillets and round corners. This will distribute the stress on the surface and will increase the part life under frighten off or creep loading. Work pieces with sharp corner becomes very assailable to surrounding and operating conditions and will behave in a very un-predict able manner under loading conditions. (Tang, 2008)4.2 Avoid Sinking and other post-process deformationsimputable to difference in the exposure temperatures, all layers within the material nerveless down at different rates with respect to each other. This leads to the outmost surfaces solidifying faster than the inner layers. This causes stress in the inward counselling and the shape of the piece starts to change. The outer layers start sinking into the workpiece and this phenomenon becomes more ascendent when there are multiple geometries of different thicknesses. To avoid such a situation, the thickness of the work piece should be kept as low as achievable according to the design. Sinking leads to discontinuities in the piece geometry and also induces unfavorable internal stresses. (Tang, 2008)4.3 Material OptimizationDuring manufacturing, attention should be stipulation to save as much material as possible without pliable the integrity of the work piece. The designing should be done in such a way that the weight of the work piece is minimum possible with optimum required strength. This will not only lead to more weight but will increase the cost unnecessarily. Care has to be taken when extra material is made later on on the molding process. (Zhang, 2007)4.4 DraftsFor easy removal of the work piece from the mold, it is essential to leave some dynamic headroom so that the mold doesnt stick to the work piece. If it sticks, it might become hard-fought to remove the work piece and it might end up deforming the work piece. In such cases, it is preferable to keep the draft angle from 1 degree to 5 degree. This angle will give ample headway to the work piece and will avoid any unfavorable situation. This parameter is essential for the liquified running of this process. (Zhang, 2007)4.5 Material response to the moldIt is very information that the material responds to the process appropriately. The material properties play the main role in defining the pro cesses to be followed or the steps to be taken. The material should be decided very carefully keeping into consideration, all the problems and complications it might face in the process. The molten form of the material should be such that it accommodates itself perfectly within the mold and cover all the fine expand within. The material should not sink subsequently solidification and neither should it warp. (Wu, 2006)4.6 tokenish work to be done of the work piece after moldingThe manufacturing should preferably be done by an experienced person. This will result in a much better and refined product and minimum refinement work will have to be done after the manufacturing. The mold plays an equally important role in the look of the product. A mold with a smooth inner surface will produce a very smooth outer surface of the work piece and hence very little work will have to be done to give the work piece a final link before being used. (Wu, 2006)5. Concerns and recommendationsThere a re few concerns which have to be taken into consideration during our design and manufacturing process of DPMSU. These are as followedIf we are to run a machine, it is to be made sure that all the create verbally information on the manual is communicated to the user as a lot of safety hazards are particularly mentioned on the user manuals. These manuals also contain procedures to be followed and precautions to be made so reading these documents is recommended before the usage of the machine, for safe and smooth operation.It is very crucial that the product is safely withdraw from the mold after solidification and nothing is damaged during its removal process. It is therefore essential that undeniable clearances may be left in the mold and draft angles are taken into consideration while designing the mold. These angles greatly assist in the removal of the work piece after it has solidified.During the design process, it is to be taken into consideration that the stress is evenly d istributed through the work piece and nowhere in the specimen should the stress be high enough to initiate a crack or cause any structural failure. Sharp edges and corners are the biggest source of high stress concentrations and must be replaced with the contoured surfaces in order to avoid stress concentration areas which may lead to mechanical failure of drill press main sliding unit during drilling operation.The mold plays a major part in defining how much time a particular process will take, how much of a share would labor cost have in the total cost and how good of a surface finish would be obtained. If these parameters are well understood and well implemented, work piece removal becomes very time and cost efficient. The machine should be completely utilised and hence the ejector pins should be taken into full use while removing the work piece.For minimum wastage, it is important that material with the most suitable condition and position is used throughout the operation. The machine should be used by an experienced person, who will make sure that minimum material is wastage after the process. As PEI is relatively more costly than other polymers, this consideration becomes important.It is necessary that the work piece is consistent and regular in dimensions.It is also to be considered that minimum post-process work is done and the manufactured specimen is gone through minimum finishing processes. To achieve this, the mold should be very smooth and the machine operator should be very experienced.Task 1 (d)Previously, injection molding is suggested for the prototyping of the component. Injection molding is also suitable for batch production of drill press main sliding unit but chase things must be taken into considerationIf injection speed is high with less solidification time, it may lead to the deformation of material with time. To observe this issue, speed of injection molding and time for solidification must be optimized in batch production.Drill pre ss main sliding units is used to hold the drill bit and holder. Due to machining operation, temperature of the assembly may rise. Moreover, unanticipated stresses on the component may occur. So, manufacturing method must yield polymeric component with optimized thermal conditions to avoid any catastrophic failure later on. (Rajput, 2008)Variations in dimensions is a common issue in polymeric components. To avoid this, synthetic hardening resins could be used while doing injection molding. These resins may enhance surface hardness of the component. (Tang, 2008)Porosity and air bubbles left in the component during manufacturing may lead to brittle failure later on. To avoid this, porosity must be prevented to occur. (Tang, 2008)ReferencesGroover, M. (2010). Fundamentals of modern manufacturing. 4th ed. late York JOHN WILEY SONS, INC.Rajput, R. (2008). A textbook of manufacturing technology. 1st ed. New Delhi Laxmi.Tang.Z.Y. (2008). Plastic act Designer GuideM,edited by Mechanical Industry Publishing House,Beijing.Wu.Z.Z,Wang.Q,Pang.Y.X,Zhang.H.APlastic Mold Design Guide,edited by National Defense Industry Press,Beijing(2006).Zhang W.HInjection Mold Design of Practical TutorialM,edited by Chemical Industry Press,Beijing(2007T. Frese et al., Electret Properties of Polyetherimides Influence of water Content and Comparison with Other High-Temperature Polymer Films, Macromol. Mater. Eng., vol. 292, pp. 582-587, February 2007.Kuznetsov, One-pot polyimide synthesis in carboxylic acid medium, High Perform. Polym., vol. 12, pp. 445-460, June 2000.