To achieve their maximum performance, the manufacturing cells are assigned to the production of a part (or product) family, rather than to the construction of a single item type. Based on this premise, when designing a cell, the main objective is to increase productivity in the production of all the parts that make up the product family.
By definition, a part family is a group of parts that have certain similarities, which make it possible for them to be processed in the same manufacturing cell. The similarities of the parts within a family may be design features, meaning, they may have similar shapes or may share common processing requirements. As implementation techniques within manufacturing cells have evolved, the mechanisms for classifying and coding the parts that make up a family have also been refined.
It is possible for parts that are physically dissimilar to form a family if they share similar processing needs. There are other factors that determine if the parts form a family, such as the existing demand or the number of times to manufacture in a period of time.
Design similarities tell us about similar shapes in the parts, while process similarities refer to the sequence of production required for these parts. In general, the two types of similarities mentioned above are not entirely related, both classifications provide various benefits in manufacturing, but in practice one tends to be prioritized over the other depending on the production objective.
Design similarities are an advantage for a new part when there is already a similar part that has been designed before, saving a lot of time at this stage. On the other hand, process similarities are very useful when creating manufacturing cells since both the part’s code and the process planning itself are reused in their operation.
Now, you will get into the details of the development of part families!
6.1 Families by design similarity
The core of the group technology is the part family, which has been defined as a group of elements that share physical similarities (form factor and dimensions) or similarities in the process route used for their production. In practice, you will find that there are certain differences between the constituent part family, however, it is the manifestation of certain similarities that allows them to be grouped into a family.
There are several methodologies to identify families of parts. The visual method is based on the physical observation of all parts of the organization and the use of the inspector's judgment to determine their grouping. The method called production flow analysis is based on the information in the process sheets to perform the classification of parts. Parts with similar manufacturing processes form a production family. The methods linked to production flow analysis are commonly associated with the application of computational algorithms that facilitate and systematize the examination of parts and their classification into families. The process related to the identification of the pieces includes the classification and codification of these, at the conclusion of this operation, there is a clear idea of what are the similarities and differences of the elements that make up the family.
6.2 Families by manufacturing similarity
In the classification and coding methodology, the similarities of the manufacturing processes and the sequence in which they are implemented for the manufacture of the part are also considered. It is very common for design features to determine or affect the decisions that are made regarding part manufacturing processes and therefore, directly influence some aspects of it.
The manufacturing characteristics of a part consist of the following:
|
|
|
|
|
|
The details of the classification and coding methodology will be covered in subsequent sessions.
Figure 1 shows two different families of parts, in the left section, although the parts share their geometry and dimensions, their processing requirements can be very different, as they can be of different material, for example, one part can be steel and another aluminum, they can also be required with very different tolerances and their volumes and production frequencies can also vary.
Figure 1. Examples of part families
The fact of grouping them in a family by their geometric similarity is very useful, since from this point of view they share the same point of view, and the design of a new similar part can be shortened if the geometric characteristics of them are retrieved from a database.
On the right side, several gears are shown that are geometrically different, but have been grouped into a part family by virtue of sharing the same process route. All are made of carbon steel of the same specification, all require the same processes: turning of the raw material, drilling of the center hole, passing through the gear generator, machining of the wedge and similar finishes. Because the parts share the different manufacturing processes, they can be considered as members of the same production family and be assigned to the same manufacturing cell.
To learn more about group technology and cellular manufacturing, check out the following video:
EmpireScreen. (2017, September 22). How It's Made: Cellular Manufacturing [Video file]. Retrieved from https://www.youtube.com/watch?v=SFmWYrLPefg&t=2s
The following link do not belong to Tecmilenio University,
when accessing to them, you must accept their terms and conditions.
The core of group technology is the part family, which is defined as a set of parts with similar design characteristics or similar manufacturing processes. When products are grouped according to design features, they provide the advantage of shortening the time spent on modeling future parts by being able to reuse elements of a previous design or parts of it, to incorporate them into the new part.
When families are grouped by manufacturing characteristics, they can be quickly and flexibly built into manufacturing cells. This process allows a medium volume of parts to be produced with the advantages of large-scale manufacturing.
When creating a part family, the first step is to group the elements using visual inspection or production flow analysis; once this procedure is completed, the elements are classified and coded. In the next topic you will learn in more detail what these systems consist of.
Make sure that you:
The following links do not belong to Tecmilenio University, when accessing to them, you must accept their terms and conditions.
To learn more about part families, watch the following video:
To learn more about identifying part families, watch the following video:
To learn more about part families grouping, we recommend reading:
To learn more about part family formation model, we recommend reading:
Through a search for information and classification, the student will apply the knowledge acquired in the creation of part families based on the design and manufacturing characteristics of a product.
To apply part identification methodologies for the preparation of part families.
Read topic 18.1 Part families from the textbook.
Individually
Xair. (2014). Xair. Retrieved from http://www.e-together.jp/xair/xair_image2.html
For educational purposes only.
Deliverable(s)
Document with the table of part attributes and the justification of the part families created.
Evaluation criteria
Description
Through an information search and classification, distinguish the concept of part family based on the design and manufacturing attributes of motorcycle components. In addition, answer a questionnaire with review questions.
Instructions
Individually