2023 BEST E-Book on #IndustrialEngineering.
INTRODUCTION TO MODERN INDUSTRIAL ENGINEERING.PRODUCT INDUSTRIAL ENGINEERING - FACILITIES INDUSTRIAL ENGINEERING - PROCESS INDUSTRIAL ENGINEERING. Free Download.
https://academia.edu/103626052/INTRODUCTION_TO_MODERN_INDUSTRIAL_ENGINEERING_Version_3_0
Lesson 250 of IEKC Industrial Engineering ONLINE Course Notes.
Engineering in Industrial Engineering - Machine work study or machine effort improvement, value engineering and design for manufacturing and assembly are major engineering based IE methods. All are available as existing methods.
Milacron Servo Injection Molding Machine.
Milacron’s servo injection molding machines offers energy efficiency, reliability, precision, and product versatility. The reduced energy use reduces the heat load on the factory and reduces maintenance and operational costs over the life of the machine.
Product Design for Manufacture and Assembly, Third Edition
Geoffrey Boothroyd, Peter Dewhurst, Winston A. Knight
CRC Press, 08-Dec-2010 - Technology & Engineering - 712 pages
https://books.google.co.in/books/about/Product_Design_for_Manufacture_and_Assem.html?id=W2FDCcVPBcAC
Note: It is important to read the books by Boothroyd to understand the full method of DFMA. The DFMA method is to be combined with Value Analysis and Engineering to do product industrial engineering. In the note only attempt is made to make readers aware of issues raised and solutions proposed by DFMA method.
Design for Injection Molding
Injection molding technology is a method of processing predominantly used for thermoplastic polymers. It consists of heating thermoplastic material until it melts, then forcing this melted plastic into a steel mold, where it cools and solidifies. The increasingly sophisticated use of injection molding is one of the principal tools in the battle to produce elegant product structures with reduced part counts.
Injection molding technology is a method of processing predominantly used for thermoplastic polymers. It consists of heating thermoplastic material until it melts, then forcing this melted plastic into a steel mold, where it cools and solidifies. The increasingly sophisticated use of injection molding is one of the principal tools in the battle to produce elegant product structures with reduced part counts.
The most common types of molds used in industry today are (1) two-plate molds, (2) three-plate molds, (3) side-action molds, and (4) unscrewing molds.
MOLD COST POINT SYSTEM
The main cost drivers are given. For each cost driver, there are associated graphs or tables to be referred to for determination of the appropriate number of points. The mold manufacturing cost is determined by equating each point to one hour of mold manufacture.
(i) Projected Area of Part (cm2)
Equations provide points for the size effect on manufacturing cost plus points for an appropriate ejection system,
(ii) Geometric Complexity
—identify complexity ratings for inner and outer surfaces according to the procedure.
—Apply Eq. to determine the appropriate point score
(iii) Side-Pulls
—identify number of holes or apertures requiring separate side-pulls (side cores) in the molding operation.
— Allow 65 points for each side-pull.
(iv) Internal Lifters — Identify number of internal depressions or undercuts requiring separate internal core lifters. — Allow 150 points for each lifter.
(v) Unscrewing Devices — Identify number of screw threads that would require an unscrewing device. — Allow 250 points for each unscrewing device.
(vi) Surface Finish/Appearance — Refer to Table identify the appropriate percentage value for the required appearance category. — Apply the percentage value to the sum of the points determined for (i) and (ii) to obtain the appropriate point score related to part finish and appearance.
(vii) Tolerance Level — Refer to Table to identify the appropriate percentage value for the required tolerance category. — Apply the percentage value to the geometrical complexity points determined for (ii) to obtain the appropriate point score related to part tolerance.
(viii) Texture — If portions of the molded part surface require standard texture patterns, such as checkered, leather grain, etc., then add 5% of the point scores from (i) and (ii).
(ix) Parting Plane — Determine the category of parting plane from Table and note the value of the parting plane factor, to obtain the point score from Equation . To determine the cost to manufacture a single cavity and matching core(s) the total point score is multiplied by the appropriate average hourly rate for tool manufacture.
DESIGN GUIDELINES
Several have published design manuals or handbooks need to be consulted for designing injection molding components. Information can be obtained from them on the design of ribbed structures, gears, bearings, spring elements, etc. Du Pont, G.E. Plastics Division, or Mobay Corporation and other plastics manufacturers provide design information associated with their engineering thermoplastics.
Generally accepted design guidelines are listed below.
1. Design the main wall of uniform thickness with adequate tapers or draft for easy release from the mold. This will minimize part distortion by facilitating even cooling throughout the part.
2. Choose the material and the main wall thickness for minimum cost. Note that a more expensive material with greater strength or stiffness may often be the best choice. The thinner wall this choice allows will reduce material volume to offset the material cost increase. More important, the thinner wall will significantly reduce cycle time and hence processing cost.
3. Design the thickness of all projections from the main wall with a preferred value of one-half of the main wall thickness and do not exceed two-thirds of the main wall thickness. This will minimize cooling problems at the junction between the projection and main wall, where the section is necessarily thicker.
4. If possible, align projections in the direction of molding or at right angles to the molding direction lying on the parting plane. This will eliminate the need for mold mechanisms.
5. Avoid depressions on the inner surfaces of the part, which would require moving core pins to be built inside the main core. The mechanisms to produce these movements (referred to in mold making as lifters) are very expensive to build and maintain. Through holes on the side surfaces, instead of internal depressions, can always be produced with less expensive side-pulls.
6. If possible, design external screw threads so that they lie in the molding plane. Alternatively, use a rounded or rolled-type thread profile which can be stripped from the cavity or core without rotating. In the latter case, polymer suppliers should be consulted for material choice and appropriate thread profile and depth.
In addition to these general rules, design books should be consulted for design tips and innovative design ideas.
REFERENCES
1. Dewhurst, P., and Boothroyd, G., Design for Assembly in Action, Assembly Eng., January 1987.
2. Rosato, D.V (Ed.), Injection Molding Handbook, Van Nonstrand Reinhold, New York, 1986.
3. Sown, J., Injection Molding of Plastic Components, McGraw-Hill (UK), 1979.
4. MacDermott, C.P., Selecting Thermoplastics for Engineering Applications, Marcel Dekker, New York, 1984.
5. Bernhardt, E.G. (ed.), Computer-Aided Engineering for Injection Molding, Hanser Publishers, Munich, 1983.
6. Design Handbook for Dupont Engineering Polymers, E.I. du Pont de Nemours and Co. Inc., 1986.
7. Farrell, R.E., Injection Molding Thermoplastics, Modern Plastics Encyclopedia, 1985-86, pp. 252-270.
8. Khullar, P., A Computer-Aided Mold Design System for Injection Molding of Plastics, Ph.D. Dissertation, Cornell University, 1981.
9. Gordon Jr., B.E., Design and Development of a Computer Aided Processing System with Application to Injection Molding of Plastics, Ph.D. Thesis, Worcester Polytechnic Institute, Worcester, MA, November 1976.
11. Ballman, P., and Shusman, R., Easy Way to Calculate Injection Molding Set-Up Time, Modern Plastics, McGraw-Hill, New York, 1959.
13. Dewhurst, P., and Kuppurajan, K., Optimum Processing Conditions for Injection
Molding, Report No. 12, Product Design for Manufacture Series, University of Rhode Island, Kingston, February 1987.
14. Schuster, A., Injection Mold Tooling, Society of Plastic Engineers Seminar, New York, September 30-October 1, 1987.
15. Sors, L., Bardocz, L., and Radnoti, I., Plastic Molds and Dies, Van Nostrand Reinhold, New York, 1981.
16. Archer, D., Economic Model of Injection Molding, M.S. Thesis, University of Rhode Island, Kingston, 1988.
18. Reinbacker, W.R., A Computer Approach to Mold Quotations, PACTEC V, 5th Pacific Technical Conference, Los Angeles, February 1980.
Designing Plastics Parts for Assembly - The pioneering development of the IBM ProPrinter.
Designing Plastics Parts for Assembly, Preface 1st Edition, by Dr. Peter Dewhurst, Department of Industrial and Manufacturing Engineering,
University of Rhode Island, November, 1993
Process Design of Injection Molding System for Umbrella Handle Based on Moldflow
ICIIP 2019: Proceedings of the 2019 4th International Conference on Intelligent Information ProcessingNovember 2019 Pages 146–150https://doi.org/10.1145/3378065.3378093
