TECHNICAL ARTICLE
Originally Printed in the January 2001 Issue of SMT
Magazine
STEP-BY-STEP: DESIGN FOR MANUFACTURE
As assembly machines, processes and process chemicals mature, electronics assemblers seek new ways to improve their manufacturing speed and quality, and to differentiate themselves from competitors. This step discusses how computer integrated manufacturing (CIM) software makes manufacturers more efficient while increasing quality and lowering overhead.
As
assembly machines, processes, and process chemicals mature, electronics
assemblers continuously seek new ways to improve their manufacturing
speed and quality, and to differentiate themselves from competitors.
Computer Integrated Manufacturing (CIM) software makes manufacturers
more efficient while increasing quality, and lowering overhead. The
applicability of CIM software within electronics assembly is very broad.
It impacts virtually every function of the factory and even beyond the
factory. Put most simply, the software is responsible for accurately and
quickly converting design and bill of materials information into
process, assembly, machine, and quality information, and getting this
resultant information to the factory floor. CIM can be thought of as
digitally leveraging maximum value from a factory’s existing human and
capital assets.
WHY COMPANIES ADOPT CIM SOFTWARE
There are countless reasons why a particular assembler chooses to deploy
CIM software. Some customers focus on converting their CAD and BOM data
into machine programs more efficiently. Others mainly seek improvements
in their assembly and inspection documentation. Still others want
quality data collection and analysis, or paperless plant-floor
documentation. In the most advanced installations, assemblers are
seeking all of these functions as well as multi-factory integration,
electronic approval management, and customer and supplier integration
into their CIM network.
Regardless of the particular requirements a factory defines for its CIM
system, one theme is common across all applications: in the never-ending
pursuit of greater efficiency and customer satisfaction, factories must
have efficient access to manufacturing information, eliminate processing
bottlenecks, get new products to the floor more quickly, and respond to
engineering changes rapidly. Increasingly, the manner in which a company
handles its information sets one assembler apart from its competition.
WHEN DOES CIM BECOME INPORTANT TO A MANUFACTURER?
Small- and medium-sized assemblers sometimes believe CIM software is a
viable option only for larger assemblers. This might be true for the
most vast and sophisticated CIM deployments, but scalable solutions are
available. It is important for virtually any assembler to consider
beginning with a small CAD/BOM conversion solution, but one ultimately
scalable into a system capable of supporting more factory functions as
they grow. Early adoption in the growth of an organization holds two
benefits: first, the factory immediately gains the throughput and
quality benefits of basic CAD/BOM conversion into outputs, such as
machine programs and assembly documentation, even with a relatively
small investment; second, as the enterprise expands, the CIM system will
scale and utilize existing data generated from the initial modules. This
strategy provides a gradual financial, operational, and cultural
transition from basic CIM into complete multi-factory integration and
beyond. Otherwise, if deployed only when the company is larger,
historical assembly information is not always available, and the
transition from manual data processing to complete CIM deployment within
a large organization can be more difficult than when smaller, initial
deployments are already well integrated.
THROUGHPUT AND PROFITABILITY IMPACTS
CIM software is unique in that, although it does not actually add direct
value to the product being produced such as would be obtained from
assembly or process machines, it radically impacts both the volume and
quality of all production in the factory.
CIM directly improves profitability by freeing time for both machines
and personnel that would otherwise be wasted in a traditional factory.
The increased speed of new product introductions, process engineering,
and engineering change implementation frees manufacturing and process
engineering time, which can then be used to process more assemblies
without increasing personnel. In an analogous situation, off-line
programming of machines and CIM-based job scheduling builds more
assemblies through the same number of machines. Dynamic web-based
supplier integration can assist both quoting and procurement speed and
lower component costs. Finally, higher quality documentation, quality
data collection systems, and more accurate CAD/BOM handling increase
quality, which reduces rework and scrap.
CIM software also indirectly impacts profitability by increasing product
quality, which in turn leads to more business. Larger systems capable of
presenting process data to customers over the Internet improve customer
retention and, certainly, satisfaction. These sophisticated systems also
simplify and expedite ISO audits by making the entire quality
documentation set, revision control history, and on-line quality manual
and approval records available to auditors through a single browser.
OUTLINE OF PRIMARY CIM SOFTWARE FUNCTIONS
In the general outline below, many sections of the overall CIM system
are individually deployable. For example, an assembler can begin with
CAD, process, and BOM handling, and eventually move into management
automation and manufacturing execution tools. These are the main CIM
system components:
CAD Conversion—
The import of both electronic design data such as Gerber or native CAD
files, as well as mechanical CAD drawings. This is the front-end to the
process, meant either to compare new data against existing product data,
or to establish a new product for introduction to the factory.
Process Development / Machine Programming / Routing—
The application of CAD data to a pre-established process routing, the
automated development of process documentation for each point in the
routing, and the automated generation of machine programs.
BOM and AVL/AML Management—
The automated import, cleaning, and organization of product data. This
portion of the system also archives product history, organizes the
hierarchy of indented BOM’s, and, in larger systems, bridges to
suppliers beyond the factory.
Revision Control—
Once BOM and product data are fully cleaned and organized, this critical
aspect of CIM software establishes electronic revision control over each
BOM, as well as the process attached to the assembly.
Management Automation—
In larger systems, electronic sign-off systems activate to convey
processed BOM and process information to parties in the organization who
are responsible for approvals. Approvals occur electronically, and are
traceable.
Manufacturing Execution—
This final, and rather vast, portion of the system conveys the “prepared
data” from prior sections to portals on the factory floor. Functions
include document viewing, on-line quality manuals, quality data
collection, paperless repair points, preventive maintenance control, and
operator feedback to engineers. This section might also include bridges
to customers.
EXPLORING SAMPLE CIM PROCESS
The best way to understand the impact of CIM in the factory is to follow
the flow of design data through a CIM-integrated facility. As mentioned
earlier, CIM systems are typically modular. It is not necessary to
deploy all of the functions explored here, and conversely, this overview
only shows a portion of the power a complete deployment would offer its
users. Also, many functions can be performed simultaneously, making the
overall throughput even greater than one might initially realize.
Design and Process Data Management—
Generally, the first process undertaken in the CIM system is the initial
importing of the CAD file. Once CAD conversion is complete, tools are
used for the development of the process routing through the factory,
complete with logical and nested decision points for quality
checkpoints. This routing is the “backbone” of all subsequent functions,
such as paperless system viewers, machine programs, final assembly
points, etc. Virtually every point in the factory is digitally modeled
so the CIM system is fully aware of the ways you manufacture product.
The CIM system automatically allocates components to the various points
of the process, allowing for user override, if necessary, balancing
lines and scheduling job ordering and changeover sequencing.
From this routing and the component assignments to the routing, the
software processes components destined for a particular machine into
specific output processors for a wide variety of assembly, process,
inspection, and test machinery. These processors are specifically
engineered for each machine and generally emulate the machine libraries
(or in the most advanced systems--use the machine libraries themselves)
such that complete, optimized programs can be transmitted to the
machinery following off-line CIM programming. One of the greatest time
savers in off-line programming is the automatic correction of the
CAD-to-machine angle convention. Some systems use offset tables for this
function while more sophisticated systems are algorithmic and fully
automated. Both types of systems correct this universal problem before
the data reaches the machinery.
Documentation is then anchored to any or all points of the factory flow.
This assembly and inspection documentation can be developed
automatically through templates assigned to each routing point to fully
automate the process.
More sophisticated systems allow the operator to assign specific
associated documentation or files to each point in the process or
reference the on-line quality manual held by the CIM system. This makes
not only the assembly documentation available, but also supporting
documents for that particular point in the process.
Bill of Materials and Product Data Management Processing—
While CAD and process information is being processed, product data is
being prepared elsewhere.
BOM Import
Bill of materials, approved vendor lists, and approved manufacturer
lists are imported through tools designed to clean common errors, and
rapidly process virtually any data source into organized product data.
Import is automated and, for contractors, remembers the formats from
each customer in the future, allowing fully automated parsing.
BOM Error Cleaning
BOM’s are electronically scanned for common errors and the users are
guided through the correction and resolution process. Original BOM’s are
maintained for comparison purposes in the future.
AVL/AML Management
Operators automatically import list of approved vendors and approved
manufacturers for a particular assembly, such that this information is
later available for procurement, quoting, and viewing on the plant
floor.
Revision Control
Revision control takes two forms at this point. First, the assembly or
“BOM” level must be given the controlling revision, and placed into the
global product tree of everything this factory has produced. Then, a
very important “process revision” is assigned to allow manufacturing
engineers to track process-specific changes independently of the BOM
revision.
Indented BOM Handling
The final product data management step involves associating indented
BOM’s. The CIM system needs to know the relationship of sub-assemblies
to upper-level assemblies, and vice versa. This is the only way complex,
nested routings on the factory floor can be controlled when work in
progress (WIP) and quality systems are deployed in the CIM system.
Electronic Approval Processes
We’ve arrived at a point where all process and product information has
been prepared, cleaned, and organized. In smaller systems, this is where
prepared data is taken to machines and to the floor simultaneously. In
larger systems, the electronic control continues with the introduction
of an electronic approval stage, which creates a “bridge” from data
preparation to manufacturing execution.
Submitting Prepared Data for Approval
When operators in process development and BOM control systems indicate
their projects are ready for approval, emails are sent to the
appropriate parties, who then log on to the system and approve the
process and BOM independently.
Pre-Production Approval
Once prepared process and BOM data is approved, the system provides a
final checkpoint in the form of production approval. This is mainly to
allow remote factories a final say as to whether data prepared elsewhere
in the enterprise is acceptable for their purposes.
Factory-Side of CIM—
The final stage of an overall CIM system provides information to the
factory floor electronically through applications (as with traditional
CIM) or through browsers (as in more advanced systems).
Setup Approvals
Operators are presented with the list of pre-production checklists
through their terminals to confirm set-up tasks. This information is
then available for quality verification after the job has been run.
Setup tasks are user-definable for every step of the process.
Paperless Documentation
Factory floor browsers present a wide variety of prepared data. Operator
aids include color-coded prints, sequence of events information, notes,
associated documents, on-line quality manuals, videos, audio
instructions, and virtually all types of mark-ups. Component searching
functions and instant part information viewing are a tremendous help to
operators. The CIM system even provides inspection sequences, flipping
views as necessary.
Data Collection
Quality data collection points (barcode or batch) gather defect
information and initiate re-routing to paperless repair stations where
assisted repairs are made with the help of browser views. Quality data
and the responses engineers make to defects improve process in the
future. Data can be analyzed to find problem areas in the products or
processes.
CONCLUSION
CIM software has reached a very exciting stage in its evolution and
development in the electronics industry. The development and convergence
of lower-cost PC’s, Internet technology, general computer proficiency,
and market demands have brought the genesis of truly collaborative
manufacturing software. These systems leverage the resources of entire
manufacturing enterprises to improve agility, quality, and
profitability. Large CIM systems are certainly very impressive, but
electronics assemblers of any size can benefit immediately from portions
of these solutions. Deploying a scalable solution today will continue to
reap benefits as CIM technology, as well as your company, advances into
the future.
Author Information:
Jason Spera, Chief Executive Officer
Aegis Industrial Software Corporation
220 Gibraltar Road, Suite 100
Horsham, PA 19044