1. Manufacturing Processes
Attributes of Manufactured Products

2. Type of Industries Industry – produces or supply goods and services
Types
Primary – cultivate and exploit natural resources
Examples – mining, agriculture, etc.
Secondary – takes outputs of primary industries and convert them into consumer and capital goods.
Tertiary – service sector
Estaremos trabajando con las industrias secundarias.
En el contexto del curso manufactura se refiere a la producción de piezas, herramientas y equipos.

3. Types of Industries

4. Secondary Industries

5. Type of Products Consumer Goods – purchased directly by consumers.
Examples: cars, personal computers, TVs, etc.
Capital Goods – purchased by other industries to produce goods and supply services.
Examples: aircrafts, railroad equipment, construction equipment, etc.
Otros incluye materiales, componentes y suministros utilizados por compañías para hacer productos.
Ej. Láminas, barras y otros suministros de metal; resinas, libricantes, etc.

6. Product Variety and Production Quantity
Low
1 to 100 units/year
Medium
101 to 10,000 units/year
High
10,001 to millions of units/year
Variety
Soft - small difference between products
Hard – products differ substantially

7. Quantity vs Variety
La relación entre cantidad y variedad es inversamente proporcional.

8. Manufacturing Capability
Planta de manufactura
Interdependencia entre materiales, procesos y sistemas.
Capability
Technical and physical limitations of a manufacturing industry.
Manufacturing processes
Product size and weight
Production capacity

9. Materials Metals (usually used as alloys) Ceramics
1/2
Metals (usually used as alloys)
Ferrous – steel, cast iron, etc.
Non-ferrous – aluminum, copper, gold, etc.
Ceramics
Compound that includes metallic and non-metallic (O, N,etc.) elements.
Clay - hydrous aluminum silicates
Silica - basis of all glass products
Alumina and Silicon Carbide – abrasive
Crystalline and glasses

10. Materials
2/2
Polymers – compound formed of repeating structural units called mers.
Carbon + one or more of H, N, O, Cl, etc.
Plastic Types
Thermoplastic
Thermosetting
Elastomers

11. In addition to the three basic categories, there are:
Composites ‑ nonhomogeneous mixtures of the other three basic types rather than a unique category
Figure 1.3 –
Venn diagram
of three basic
Material types
plus composites

12. Geometric Attributes

13. Shape Classification

14. Machine Tool Movement and Control

15. Limitations Axial symmetry Nonrotational symmetry Surface
Two dimensional axes
Nonrotational symmetry
Min of two dim axes
Surface
Min 1 axes

16. Surface Limitations

17. Dimension ANSI (American National Standards Institute)
Numerical value expressed in appropriate units of measure and indicated on a drawing and in other documents along with lines, symbols and notes to define the size or geometric characteristic, or both, of a part feature.
Length, width, height, diameter, angles, etc.
12’’
3’’
4’’

18. Dimensioning Systems U.S. Customary System (USCS)
Inch (in)
International System (SI)
Meter (m)

19. Tolerance
ANSI
The total amount by which a specific dimension is permitted to vary.
Tolerance = Max Limit – Min Limit
Types
Bilateral
Unilateral
Limit dimension
Variations occur in any manufacturing process, which are manifested as variations in part size.
Tolerances are used to define the limits of the allowed variation.

20. Bilateral Tolerance
Variation is permitted in both positive and negative directions from the nominal dimension
It is possible for a bilateral tolerance to be unbalanced; for example, ,
Figure 5.1 ‑ Ways to specify tolerance limits for a nominal dimension of 2.500: (a) bilateral

21. Unilateral Tolerance
Variation from the specified dimension is permitted in only one direction, either positive or negative, but not both
Figure 5.1 ‑ Ways to specify tolerance limits for a nominal dimension of 2.500:
(b) unilateral

22. Limit Dimensions
Permissible variation in a part feature size, consisting of the maximum and minimum dimensions allowed
Figure 5.1 ‑ Ways to specify tolerance limits for a nominal dimension of 2.500:
(c) limit dimensions

23. Tolerance must be…
close enough to allow functioning of the assembled parts.
as wide as functionally possible.

24. Tolerance

25. Tolerances and Manufacturing Processes
Some manufacturing processes are inherently more accurate than others
Examples:
Most machining processes are quite accurate, capable of tolerances = 0.05 mm ( in.) or better
Sand castings are generally inaccurate, and tolerances of 10 to 20 times those used for machined parts must be specified

26. Other Attributes
See table 5.1
Angularity – a part feature is at specified angle relative to a reference surface.

27. Other Attributes
See table 5.1
Circularity/Roundness – the degree to which all points on the intersection of the surface and a plane perpendicular to the axis of revolution are equidistant from the axis.

28. Other Attributes
See table 5.1
Concentricity – the degree to which any two (or more) part features have a common axis.
5" OD x 2" ID x 2" long. 5' OD and 2' ID will be concentric within .020' TIR (5" OD - 2" = 3" separation). 

29. Other Attributes
See table 5.1
Cylindricity – the degree to which all points on a surface of revolution are equidistant from the axis of revolution.

30. Other Attributes
See table 5.1
Flatness – The extent to which all points on a surface lie in a single plane.

31. Other Attributes
See table 5.1
Parallelism – the degree to which all points on a part feature are equidistant from a reference plane, line or axis.

32. Other Attributes
See table 5.1
Perpendicularity/ Squareness – the degree to which all points on a part feature are 90° from the reference plane, line or axis.

33. Other Attributes
See table 5.1
Straightness – the degree to which a part feature is a straight line.

34. Surfaces What we touch when holding a manufactured part.
Nominal surfaces – intended surface contour.
Actual surfaces of a part are determined by the manufacturing processes used to make it
Importance
Aesthetic
Affect safety
Friction and wear
Affect mechanical properties
Affect assembly
Smooth surfaces make better electrical contacts
The nominal surfaces appear as absolutely straight lines, ideal circles, round holes, and other edges and surfaces that are geometrically perfect.
The variety of manufacturing processes result in wide variations in surface characteristics.

35. Surface Components
The topography and geometric features of the surface:
When highly magnified, the surface is anything but straight and smooth. It has roughness, waviness, and flaws.
Figure 5.2 ‑ A magnified cross‑section of a typical metallic part surface

36. Surface Attributes
It also possesses a pattern and/or direction resulting from the mechanical process that produced it.

37. Four Elements of Surface Texture
Roughness - small, finely‑spaced deviations from nominal surface determined by material characteristics and process that formed the surface
Waviness - deviations of much larger spacing; they occur due to work deflection, vibration, heat treatment, and similar factors
Roughness is superimposed on waviness

38. Lay:
predominant direction or pattern of the surface texture

39. 4. Flaws - irregularities that occur occasionally on the surface
Includes cracks, scratches, inclusions, and similar defects in the surface
Although some flaws relate to surface texture, they also affect surface integrity

40. Surface Attributes
It also possesses a pattern and/or direction resulting from the mechanical process that produced it.

41. Surface Roughness and Surface Finish
Surface roughness - a measurable characteristic based on roughness deviations
Surface finish - a more subjective term denoting smoothness and general quality of a surface
In popular usage, surface finish is often used as a synonym for surface roughness
Both terms are within the scope of surface texture

42. Surface Roughness
Average of vertical deviations from nominal surface over a specified surface length
Figure 5.5 ‑ Deviations from nominal surface used in the two definitions of surface roughness

43. Surface Roughness Equation
Arithmetic average (AA) is generally used, based on absolute values of deviations, and is referred to as average roughness
where Ra = average roughness; y = vertical deviation from nominal surface (absolute value); and Lm = specified distance over which the surface deviations are measured

44. An Alternative Surface Roughness Equation
Approximation of previous equation is perhaps easier to comprehend:
where Ra has the same meaning as above; yi = vertical deviations (absolute value) identified by subscript i; and n = number of deviations included in Lm

45. Cutoff Length
A problem with the Ra computation is that waviness may get included
To deal with this problem, a parameter called the cutoff length is used as a filter to separate waviness from roughness deviations
Cutoff length is a sampling distance along the surface. A sampling distance shorter than the waviness width eliminates waviness deviations and only includes roughness deviations

47. Figure 5.6 ‑ Surface texture symbols in engineering drawings:
the symbol, and (b) symbol with identification labels
Values of Ra are given in microinches; units for other measures are given in inches
Designers do not always specify all of the parameters on engineering drawings

48. Material Properties
Mechanical – strength, toughness, ductility, hardness, elasticity, fatigue, creep, ratios
Physical – density, specific heat, thermal expansion, thermal conductivity, melting point, magnetic and electrical qualities
Chemical – oxidation, corrosion, degradation, toxicity, flammability
Manufacturing – manufacturability, effects on product properties, service life, cost