1. Improving Productivity-When to Consider Automation
Chapter 5

2. When Automation is Needed
Automation considered cost reduction
Assumed less operating costs
Justified by the amount of labor that can be eliminated
Doesn’t always reduce costs

3. General Motors case study
1960’s investing heavily in robotics and automation
Tried to justify cost reduction by measuring work productivity
Total labor hours needed to produce an automobile
Discovered that automation doesn’t always improve productivity
Doesn’t reduce waste

4. Automation makes sense when:
The manufacturer needs to increase the rate of production substantially
A human being needs to be removed from an unsafe/unhealthy production process

5. Pre-Automation Process
Before automation waste areas need to be eliminated
Review waste categories in all major departments

6. Examples of waste Category Example Non-value adding activities
Inspections, repair/rework, taking parts in and out of storage
Uneeded materials
Parts that can be eliminated or have no function in the product
Unneeded operations
Making, using or assembling unneeded parts
Delays and downtime
Materials arriving late, broken machines, absence of workers
Loss
Spoiled, scrap, or unusable materials that are thrown away
Duplication
Making extra product in anticipation of defect/scrap. Making two or more styles of a product that have the some function

7. Design for Assembly (DFA)
Simulates assembly of the product, to be evaluated in terms of its suitability to modern methods of assembly
If followed most products can be assembled for less than with automation

8. DFA Guidelines Design parts that are symmetrical
Doesn’t have to be oriented
Makes automation easier
If it can’t be symmetric, make it very asymmetric
Obvious which way it is assembled
Makes it easier for the operator to install correctly
If a part tangles or jams together
Slows down operators
Eliminate parts that are hard to handle

9. Make insertion and fastening of parts simple and fast
Design a fixture to hold the components during assembly
Provide chamfers, insertion guides, and ample clearance for parts being inserted
Create a sequence of assembly in one axis
Design parts to be oriented properly before they are released
Standardize on commonly available fasteners and fastening techniques

10. Reducing the number of parts
Eliminate parts and reduce variety
Least parts needed to make the product function
Determine the minimum number of parts by asking:
Does the part have to move relative to other parts in the assembly when the product is in operation?
Does the part have to be made from special material different from the other parts of the assembly?
Does the part have a unique function even though the answer to the first 2 questions was no?

11. Bathroom Scale case study
Mechanical bathroom scale consisted of:
17 separate stamped metal parts
6 spot welds
7 fasteners
Design was popular but overseas competition was making cheaper products
Looked into automation
Wouldn’t decrease their selling cost much
Instead they went through DFA

12. Reduced design to 6 parts 5 fasteners (from 7) No spot welds (from 6)
2 were stamped and assembled in the press
5 fasteners (from 7)
No spot welds (from 6)
Cost of retooling was minimal compared to automation

13. Their DFA program was a team with representatives from:
Product engineering
Production engineering
Purchasing
Sales
Cost accounting
Plant personnel

14. Mechanization of Assembly
2 tasks of assembly:
Acquiring a component
Adding the component to the assembly
Must establish a sequence for assembly that meets DFA guidelines
Make assembly simple and fast
Identify the part that will be a chassis
Other parts are assembled into
If no chassis, an assembly jig is used

15. Common mechanization:
Mechanization-making or assembling things with machines and tooling to increase the rate of production
Common mechanization:
Screw guns
Riveting machines
Staplers
Nail guns
Part feeding (parts, fasteners)
Positioning
Clamping

16. Automated Manufacturing Systems
Chapter 6

17. Automation
Is a repeatable operation or process that relies on several components working together
Building blocks of automation:
Repeatable operation or process
Control system
Material placement system

18. Nature of Automation
Primary goal is to increase productivity

19. Mechanization vs. Automation
Increase rate
Reduce cycle time of operator
Enhances machine operator’s abilities
Automation
Relies on mechanisms
Does not require an operator

20. Soft Automation
Handle a wide variety of shapes and material characteristics
Complicated control system
Simple looking hardware (fewer details)
Use of computers, software and sensors

21. Control Systems Operator controls the machine Start/stop
Manual Control
Automated control
Operator controls the machine
Start/stop
Make adjustments
Pushing a button
Computer system monitors the operation
Must also monitor quality

22. Numerical Control
Automating manufacturing processes by describing tool paths
Movement along an axis or vector
1801
French textile weaver used punch cards with their looms to control patterns
1949
Michigan machining company used punched tape to create contoured parts of helicopter blades
Used information on punched tape
1952
Massachusetts Institute of Technology developed a machine and computer to actuate the machine motors
1958
Kearney and Trecker developed the first machining center
Machine could change tools automatically

23. How NC Controls a Machine Tool
NC program contains instructions for movement in each axis
Instruction is sent to a control unit (MCU) that controls electric motors
Motors are attached to lead screws
When the motors turn the screw a sensor measures the movement

24. NC Programming The Code used to control the machine
Computer software used to generate the code
CAD/CAM system
Use CAD model

25. Material Feeding
Consists of orienting and providing a method of propelling components
Used in automation to provide parts to assembly equipment