Spelling suggestions: "subject:"assembly line methods."" "subject:"asssembly line methods.""
51 |
Modeling and analysis of production lines with and without preventative maintenanceJanuary 1983 (has links)
Yuhuan Pan, Stanley B. Gershwin. / "April 1983" / Bibliography: p. 45-46. / "Contract No. DAAK11-82-0018"
|
52 |
Integration and control of feeding devicesMangala, Ngongo Katembo 12 September 2012 (has links)
M.Ing. / Parts feeding devices or feeders are used in automated assembly systems to deliver correctly oriented parts to the assembly station workhead. These devices play an important operational role since feeding is one of the major operations involved in an automated assembly process. However they account for much of the cost of an automated assembly system because most of the engineering time spent to develop such a system is used to devise a means of feeding the components in the correct orientation for the assembly process. This thesis describes the implementation of an integrated and computer controlled feeding and transfer system. The system consists of a vibratory bowl feeder for selecting, orienting and feeding parts and a flat conveyor belt for transferring parts to a prescribed location. The work focusses mainly on the design and analysis of the bowl feeder, on the mechanical and information interfacing aspects of the integration problem and on the control of the system. Sensing and electronic control circuits were also built to complete the system. The system implemented is to be integrated at a later stage with an industrial robot for handling purposes. Therefore, some issues related to the handling of parts from the conveyor belt by the robot are also discussed. Experimental results show that the recommendable operating frequency for the vibratory feeder is close to the value predicted by theoretical analysis. Several concurrent activities with critical time constraints and different periods were involved in the system, making the control more difficult due to the limited control capabilities of Visual basic, an easy to learn programming language used to implement the control program and the relatively slow speed of the computer used Nevertheless, it was observed that for feed rates close to 3 parts/min, the program developed performs well regarding the random control of the flow rate of parts on the conveyor, parts position and speed profiles obtained compare satisfactorily with the corresponding theoretical profiles. Recommendations for the integration of the robot to the system are made.
|
53 |
Estimating correlations between certain operation finishing times to approximate the transient performance of stochastic assembly systems /Saboo, Surendra January 1986 (has links)
No description available.
|
54 |
The Development of an Automated Production SystemCardinal, Brian M. 01 January 1984 (has links) (PDF)
This paper describes the development of an automated production system recently completed by the Martin Marietta Aerospace Division, Orlando, Florida, for the assembly, inspection and test of printed circuit boards. The project began in January 1981 with the purpose of increasing the then existing production capability and to create the building block for the total automation of the printed circuit board assembly area of the plant in Ocala, Florida. The system was implemented using a combination of off the shelf equipment modified and integrated to create a single production system. The system employs much of the new production philosophies tailored to meet the particular needs of Martin Marietta and to fulfill present production requirements as well as future production projections. During the development and implementation of this project, flexibility within the team was required to accommodate for the unforeseen problems which surfaced. The actual work required to perform this task far exceeded the expectations of the team and the company. This document covers all facets of this project, from inception to operation, and describes the problems encountered and lessons learned throughout the project.
|
55 |
Comparison of robotic positional control strategiesEucker, David A. January 1987 (has links)
A comparison of robotic positional control strategies was done using computer simulation on a three degree-of-freedom manipulator. The manipulator was subjected to different payloads, trajectories at different velocities, varying different controller sample rates and different motor saturation levels. The control schemes studied were the proportional plus integral plus derivative (PID) method, computed torque method, resolved motion rate control (RMRC) method and the model-referenced adaptive control (MRAC) method.
These schemes were representative of three categories of robotic positional controllers - Joint Space control, Cartesian Space control and adaptive control. The criteria used for comparison were the maximum trajectory error, the maximum electrical controller. / M.S.
|
56 |
Unit loads in assembly component deliveryOcceña, Luis G. January 1983 (has links)
A new way of looking at scheduling and lot sizing is proposed by embedding material handling considerations in the determination of optimum delivery policies for a single stage, uniform demand assembly system in a finite horizon. Unit loads are used in place of lots; material handling and container costs are charged; and area and material handling constraints are imposed. A solution procedure based on a delivery period matrix is used to solve the minimization problem. Computational experience is provided. A special case of uniform delivery intervals is taken up and a discussion is given on variance penalty. / M.S.
|
57 |
Optimal part delivery dates in small lot stochastic assembly systemsSrivastava, Rajiv K. January 1989 (has links)
An important issue in the design and operation of assembly systems is the coordination of part deliveries and processing operations. These decisions can have a significant impact on inventory cost and customer service. The problem is especially complex when actual delivery and processing times are stochastic in nature, as is the case in small lot manufacturing.
In this research a new methodology is developed for determining optimal part delivery dates in stochastic small lot assembly systems. This methodology is based on the descriptive model that comprises of taking the maximum of several random variables. The part arrival and processing times are assumed to follow various known probability distributions. The model includes consideration of limited buffers between stations. The overall objective is to minimize the expected total of part and subassembly inventory cost, makespan cost and tardiness cost.
An approach based on the optimization of individual stations in isolation is used to obtain the part delivery dates at each station. Comparison of the approach with the nonlinear programming based approach to the problem indicates that it generates almost as good solutions in a fraction of the computation time. This approach is then used to study system behavior under various operating conditions. Results indicate that the Iognormal and gamma distributions result in higher total costs than the normal distribution. However, the normal distribution can be used to determine part delivery dates even if the actual distribution is Iognormal or gamma, with relatively small errors compared to the solutions obtained using the correct distribution. Variability is the most important factor in the design of the system, and affects the determination of due dates, buffer capacity requirements, choice of distribution, and estimates of system performance. The role of buffer capacities, however, is not very critical in the design of small lot unbalanced lines. / Ph. D.
|
58 |
Conceptual design of a fixtureless reconfigurable automated assembly systemDymond, F. S. D. 12 1900 (has links)
Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: The conceptual design of a fixtureless reconfigurable automated spot welding
system for manufacturing subassemblies for residential circuit breakers was
investigated. This research was aimed at developing a possible low cost automation
alternative to a South African industrial manufacturer, which is presently heavily
dependent on personnel for manual assembly of their core products.
System reconfiguration allows for the assembly of a range of subassemblies with
geometric component variation on a given system configuration, as well as the
potential for the system to be reconfigured to assemble other ranges of circuit
breaker subassemblies.
The subassembly selected as focus consists of six different components, which vary
geometrically from one product variant to another. A fixtureless approach was
selected, to minimise reconfiguration down time and the need for reconfigurable
fixtures since reconfigurable fixtures have not found significant acceptance in
industry. This varies from a fixture-based approach, which was considered in related
research.
The conceptual assembly system presented here consists of the following modules:
a flexible vision based part feeder, twin 6 DOF robotic manipulators each with a
multipurpose gripper, and a stationary spot welding station. Critical conceptual
design elements were further investigated to refine their selection and confirm
feasibility with respect to the target industry application. This process ended with a
preliminary cost estimate which served as a basis for comparison between the
fixtureless, fixture-based and present manual assembly process. The fixtureless
concept was overall more expensive than the fixture-based concept, primarily
because of the limits to production throughput. The fixtureless concept was
however cheaper than the present manual assembly approach but had a far longer
payback period than desired by the industry. The complexity and possible
uncertainties of the concept combined with the long payback period indicated that
the fixtureless concept is not suitable for the target application. / AFRIKAANSE OPSOMMING: Die konsepsionele ontwerp van 'n setmaatlose herkonfigureerbare outomatiese
puntsweisstelsel vir die vervaardiging van subsamestellings van huishoudelike
stroombrekers is ondersoek. Hierdie navorsing is gemik op die ontwikkeling van 'n
moontlike lae koste outomatiese alternatief vir 'n Suid Afrikaanse industriële
vervaardiger, wat tans sterk afhanklik is van werkers wat die montering van hul kern
produkte met die handsamestelling doen. Stelsel herkonfigurasie laat die
samestelling van 'n reeks subsamestellings, met geometriese komponentvariasies,
op 'n gegewe stelsel toe, asook die potensiaal om die stelsel te herkonfigureer om
ander reekse van stroombreker-subsamestellings te monteer. Die subsamestelling
wat as fokus gekies is, bestaan uit ses verskillende komponente met geometriese
verskille van tussen produkvariante. 'n Setmaatlose benadering is gekies ten einde
aftyd vir herkonfigurasie en die noodsaaklikheid van herkonfigureerbare setmate te
minimeer, omdat laasgenoemde nie noemenswaardig deur die industrie aanvaar
word nie. Hierdie benadering verskil van 'n setmaat-gebaseerde benadering wat in
verwante navorsing ondersoek is.
Die konsepsionele monteringstelsel wat hier aangebied word, bestaan uit die
volgende modules: 'n plooibare, visiegebaseerde voerapparaat; dubbele sesvryheidsgraad
robotiese manipuleerders, elk met 'n veeldoelige gryper; en 'n
statiese puntsweisstasie. Kritiese elemente van die konseptuele ontwerp is verder
ondersoek om hul keuses te verfyn en uitvoerbaarheid in die teiken industriële
toepassing te bevestig. Hierdie proses is afgesluit deur 'n voorlopige kosteraming
wat gedien het as 'n basis vir die vergelyking van setmaatlose, setmaat-gebaseerde
en die huidige handsamestellingstelsels. Die setmaatlose konsep was oorhoofs
duurder as die setmaat-gebaseerde konsep, hoofsaaklik as gevolg van beperkings op
die produksie-deurset. Die setmaatlose konsep was egter goedkoper as die huidige
handmonteringsproses, maar het 'n veel langer terugbetalingstydperk as wat deur
die industrie verlang word. Die kompleksiteit en moontlike onsekerhede van die
konsep, gepaard met die lang terugbetalingstydperk, dui daarop dat die setmaatlose
konsep nie vir die teiken toepassing geskik is nie.
|
59 |
A hidden Markov model approach to force-based contact recognition for intelligent robotic assemblyNgan, Choi-chik., 顔才績. January 2002 (has links)
published_or_final_version / Industrial and Manufacturing Systems Engineering / Doctoral / Doctor of Philosophy
|
60 |
Application of a technological-economic model of assembly techniques to programmable assembly machine configuration.Kondoleon, Anthony Spyridon January 1976 (has links)
Thesis. 1976. M.S.--Massachusetts Institute of Technology. Dept. of Mechanical Engineering. / Microfiche copy available in Archives and Engineering. / Includes bibliographical references. / M.S.
|
Page generated in 0.131 seconds