In advance of start-up of production, production and maintenance workers must be trained according to a specific plan designed by manufacturing managers and performed in collaboration with working means and suppliers of information systems.
Normally, it is allowed that productive flow speed will be initially low and only progressively reach the project target after a certain time from the start of production (due to the ‘‘learning curve’’). Conversely, it is not allowed, either initially or otherwise, for products to be sold that do not fulfill the qualitative and functional customer requirements.
management activities during the product’s life cycle, defining a concept of ‘‘net enterprise’’ (including first level suppliers, plant dealers and after sales technical centers).
Furthermore, PDM represents the informative backbone for the way in which accounting is done for single product direct costs, as we will see subsequently.
In PDM, productdata managementrequires the operative features represented in Fig.2.4.
Datastorageruns as follows:
• data are structured according to a product composition tree (bill of materials) and process logistics (manufacturing job descriptions);
• all documents in electronic format are referred to reference models;
• original data (technical specifications, CAD part design…) are stored as virtual data.
Examples of virtual data:
• file typology, its position in a file system, creation data, author…;
• link between a CAD file and a text file describing it;
• raw material technical characteristics, requirement and unitary cost of each part number.
Dataresearchruns as follows:
• virtual data can be used as an information source or as searching keys in the system database;
• data can be accessed through WBS visualizations.
Starting datamanagement and updating, i.e.changes, runs as follows:
• PDM users work on original data copies (consultancy, changes);
• all changed data are recorded as revisions of the original data;
• original data always remain in memory.
Research Storage
Change
reference models
structured data and correlations (virtual data)
virtual data using data exploration easyness
progressive «release», by storing previous references historical data storage and work his tory
Fig. 2.4 PDM features
PDM allows for managing technical data and the creation of part number designs and the updating processof the product, checking the following operative aspects:
Work management, which means establishing who can do what:
• system users are classified by role, according to their position in the organization;
• specific possibilities for accessing and processing data for each role.
Workflow management, which means establishing who must do what and when:
• the system considers a ‘‘standard workflow’’ (execution, check and approval), for all the items used in the activity;
• the system automatically sends the updated data to the responsible parties, according to the above-mentioned ‘‘standard workflow’’ and established pro- cedures for delivering the design’s ‘‘release’’.
Work history management,which means establishingwho has done what and when:
• the system tracks access to data and completed operations (release, changes, approval…);
• at every moment, it is possible to know the work history of all data (model and document).
Simultaneous engineering, which means establishing who does what with whom:
• the system foresees potential for collaboration between individual positions and departments;
• in this way, revisions are automatically posted (new releases), keeping the participants in the project constantly informed.
Modern PDM systems are integrated with other enterprise information tech- nology systems, on the condition that they have homogeneous environments (same CAD/CAE/CAPE systems), as shown in Fig.2.5.
An integrated information technology system allows PDM to deal with the other systems used in the product/process development, for:
• creating input data(design engineering settings);
• visualizing designed parts and their position on complete modules;
• updating and spreading out of data, allowing electronic research.
The main advantages of a homogeneous information technology environment are:
• access to same data from different hardware platforms;
• same CAD models and structural data available in the same environment;
• availability of most up-to-date data.
Internet and Intranet connections allow for the elimination of geographical restrictions and improve interaction, with the application of necessary protections for technical documents, according to policies established between provider and supplier.
The heart of PDM is theProduct Breakdown Structure(PBS), described in the following section.
PBS structure ishierarchicaland is represented in Fig. 2.6(tree diagram). The final product is on the top and is deployed, through different levels, down to single components, subassemblies and raw materials at the base.
Automatic data processing, according to the tree diagram, means assigning a code to each link on the structure; through the code, each part is associated with the assemblies and subassemblies to which it belongs.
In describingPBSfunction, we will use the following terms:
• element =design code or part number;
• assembly or subassembly =secondary group code
• usage coefficient=number of elements necessary to complete a final product
• completed elements and final group weight =it corresponds to element designs and is calculated based on volume and weight of direct materials, including the fluid ones (metal external parts and polymers, paints, lubricating, structural glues and sealers…).
This data, referred to as the several typologies of basic materials, is necessary for statistical control and technical and economic analysis: comparisons between theoretical and real data, comparisons between models, benchmarking between different solutions, cost effect analysis as a consequence of raw material price variations…
PDM
CAD Digital
Mockup Data structure
Basic model, versions and optional
requirements management Research and interactive consultancy
Elements dimension and related technical data
Function/Position on modules
Visualization of modules and subassmbling Matching and assembling checks
. .
. . . .
.
Fig. 2.5 PDM integrated information technology system
Some significant examples:
• powertrain system, the completion of body brackets is a primary assembly of level B, but when installed on the vehicle, it is considered to be of level A.
• at level C, we find the principle mechanics groups included in the powertrain system:complete engine, transmission, gearbox, electrical systems, brackets for connections to the body.
• remaining on the complete engine, at level D, we find the engine short block (includingcylinders, blocks, engine shaft, con rods and pistons…) and the head cylinder group, including valves.
• then, at level E, we find different primary groups and subgroups:head cylinder, pistons, valves, injectors, inlet and exhaust manifolds, flywheel, auxiliary con- trols and fixing elements…
• finally, at level F, we find sub-components, specifichalf transformed elements and rawmaterialsfor each of the above elements.
Even as an example,material requirementfor an exhaust valve is the part of a steel bar used for hot printing and the quantity of coating reported on the cone valve before finishing the operation. If, for example, the engine is a four-cylinder, with four valves for each combustion room, theusage coefficientfor the element exhaustion valve is eight for each product series.
A
B1 B2 B3 Bn
Cn1 Cn2 Cnk
Dnk1 Dnk2 Dnkj
Enkj
Fnkj
= final module
= 1 level subassembly (primary group)
= 2 and 3 level subassemblies (secondary groups)
= completed elements
= partially completed elements
= raw material (gross requirement) A
B
C
D E
F
Fig. 2.6 PBS Hierarchical structure
Despite being unambiguous, the structure of a car model is developed by steps:
‘‘macrostructure’’ is determined during the project setting phase, ‘‘analytical structure’’ during the technical project development phase and ‘‘bill of materials’’
during the manufacturing engineering phase. This classification is typical of automotive processes, depending on the complexity of the vehicles.
Figure2.7, according to the ‘‘best practices’’, represents the time sequence flow occurring from project set-up and industrialization to the definition and codifica- tion of the product structure and production competency.
Starting from PBS, the Project Manager, as indicated inSect. 2.2, defines the Work Breakdown Structure (WBS) and controls project development, assuring that:
• professional resources and technical structures will be available on time;
• value/cost targets will be reached, according to PMS items;
• defined times and motions for each activity and phase will be respected, in relation to time to market, with special reference to the ‘‘key process points’’
mentioned in this section.
PMS being organized in ‘‘principal modules and functional subassemblies’’, it is not necessarily responding to physical aggregation of the product.
Some examples of ‘‘functional subassemblies’’ as single items ofPMSthat are related to several ‘‘physical modules’’ of the product, according to assembly procedures:
macrophases MACRO STRUCTURE
SETTING
DESIGNING INDUSTRIALIZATION PRODUCTION
PMS PBS BILL OF MATERIALS
PROJECT TESTING PROCESS TESTING
OPERATIONS MANAGEMENT
VALUE/COST ANALYSIS PDM
processing step
Testing and updating
Fig. 2.7 Product structure codification process
• engine supply system, partially allocated to the engine and partially installed in the fuel tank and on the vehicle;
• engine cooling system, partially allocated to the engine and partially installed on the ‘‘front-end’’ of the vehicle;
• steering wheel system, partially allocated to the front suspension module and partially directly installed on the vehicle;
• brakes controlling system, partially allocated to the wheels group (corner) and partially directly installed on the vehicle;
• air conditioning system, partially allocated to the engine (compressor) and partially installed in cockpit module and directly on the vehicle;
• electrical equipment (wirings and electronic switchboards);
• electronic devices for engine, brakes and vehicle suspension control…
It is important to note that for each element design in the PBS a relative function code can be assigned, according to thePMS. As the project is developed, each ‘‘principal module and functional subassembly’’ becomes an ‘‘element design’’, which is described in the product breakdown structure, applying classical criteria of ‘‘equipment construction’’.
Practically, PBS accurately describes the product’s physical structure and is extended to 1st level suppliers and their sub-suppliers, according to ‘‘make- or-buy’’ competency.
Using thePBS, it is possible to:
(a) manage the designs and standard carry-over solutions with other product lines;
(b) underline links between elements/subassemblies and final product;
(c) establish precise ‘‘make-or-buy’’ competency for each element;
(d) activate manufacturing engineering plan for the ‘‘making’’ of parts;
(e) activate purchasing orders for the ‘‘buying’’ of parts;
(f) confirm costs for module components, considering the targets defined in the setting phase, according to the PMS.
PBS relative to product range items are the basic information of the PDM system mentioned above.
Once the manufacturing engineering plan for ‘‘making’’ parts and purchasing orders for ‘‘buying’’ parts have been completed, it is possible to compare analytical data derived from the executive project, with the global cost target of the product, established in the economic initiative of industrialization. Gap analysis is managed according to thePMS, for allocating responsibilities to the single project leaders and co-design suppliers, consequently leading the countermeasure research on running. Normally, the Project Manager has a safety margin for changes and unexpected events, outside of PMS, for what he could do in consequence of documented needs.
The Bill Of Material (BOM)follows PBS (and, in many cases, is the same document) and admits elements and subassemblies (physical modules) in con- sideration of making processes and manufacturing procedures for subassemblies
and final modules. The information in it is related to a specific product (series of elements, subassemblies and assemblies) charged to a single plant and includes:
• ‘‘design code’’ relative to a single product element, subassembly and final assembly managed by the shop floor;
• eventual alternative design codes for the same function;
• use of coefficient of the single element, for the same product series;
• ‘‘making’’ or ‘‘buying’’ competency, shop in charge of manufacturing, depart- ment in charge of supplying and direct material receiving;
• quantitative and qualitative specifications for raw material and components necessary for the ‘‘making’’ process (identification code of the material, gross requirement for the single element and use coefficient during transformation process).
Moreover, along with the data and correlations specified in the PBS, the bill of material also includes the raw material and pre-machined parts necessary for manufacturing each element, including waste of material consequent to the transformation process and not directly recoverable in the same process (gross unitary requirement).
This data refers to the several typologies of materials as so-called ‘‘undefined materials’’, or half machined parts with a specific design. For undefined materials, the standard requirement is expressed in weight unit, or geometrical unit, depending on the features of the transformation processes. For example, in foundries, the weight unit is used for the single ‘‘shoots’’, without waste recovered in the same process, in metal printing, surface unit referring to a specific thickness of the sheet of metal is used (convertible in a weight unit without the waste of metal re-used to print other parts), and for extrusions and laminated parts, a length unit referring to a specific section is used (also convertible in a weight unit).
For all these reasons, the bill of material, despite its name, is more than a list, having a wide variety of information.
The standard requirement, as mentioned above, related to the purchasing price and to the utilization coefficient, allows for the allocation of the direct material costs to the single element produced and thus the cost of each fin- ished element to the final product, applying the utilization coefficients to the elements defined in the bill of material.
The difference between the real consumption of raw material and the standard requirement is due to the losses caused by process failures and production scraps.
In Fig.2.8, the logical productive flow for theBOM is represented.
Thebill of materialshas to be updated constantly during the entire life of the industrial product cycle, as it allows us to:
(a) manage production planning and final product delivery to the customers;
(b) manage the ‘‘completely knocked down’’ (so called CKD) elements for the Assembling Plant operating in ‘‘co-makership’’;
(c) manage the process of order emission to the suppliers and the direct material requirement process (MRP procedures);
(d) manage spare parts and after sales assistance;
(e) check the utilization degree of direct materials;
(f) identify direct material in input from the final product in output, feeding the accountability financial system, for the billing as well as for stock management;
(g) assign the ‘‘cost centres’’, the standard working times for each element, sub- assembly and assembly, complying with the standard operative procedures;
(h) aggregate the production costs for each element and consequently assign them to the final product.
Through the PDM system, which normally works on a ‘‘PC-based’’ system with a network connection, it is easy to access all the technical documentation of the project (element designs, assembly schemes, material technical speci- fications….) and elaborate documents necessary for product management. It is possible as well to elaborate the manufacturing engineering documentation (standard operative procedures, control instructions…) necessary for process management.
Let us end this section by showing the chart in Fig.2.9as to how the database can be connected on a wide band system throughout the company intranet.
PROCESSO DI PROCESSO DI
FINAL PRODUCTS
RAW MATERIALS
1STLEVEL GROUPS
FINAL ELEMENTS MACHINED
ELEMENTS
2ND 3RD LEVEL GROUPS
ASSEMBLY PROCESS MANUFACTURING PROCESS
-
Fig. 2.8 BOM productive flow