automated
assembly and testing in medical device production
A
road map of the key issues to consider when sourcing complex
integrated assembly and testing systems
Featured
in Medical Device Technology October 2002
Unpacking
the complexities
The larger pharmaceutical and medical device
manufacturing companies are increasingly realising that
by developing novel drug delivery mechanisms, the life of
a drug can be significantly extended. This, combined with
the development of other complex medical devices requiring
volume-production methods, has led to an increase in the
use of combined assembly and testing systems. These systems
integrate the use of assembly processes with sophisticated
testing procedures that require specialist automated assembly
and data handling. This article outlines the key issues
to address when sourcing this equipment.
Capturing
the requirements
| It
is often difficult for system integrators to properly
capture the manufacturer’s requirements for an
automated production system. Sometimes, this is because
a minimal specification is supplied and essential information
has to be coaxed out of the manufacturer. At the other
extreme, the enquiry consists of two pages of technical
specifications hidden within a forest of commercial,
contractual and general specifications, which confuse
the assessment of the requirements. |
|
|
Pallet-based
plastic component assembly in an automotive application |
Estimating
volumes
When considering
an automated production process, it can be difficult to
estimate peak volumes. This is particularly the case with
a new product start-up when the marketing data is variable.
The techniques used for automated assembly may be considerably
different for manufacturing 1 part/min on a single day shift
compared with 1 part/s in a 24/7 regime. Although difficult
to assess, it is essential to have a clear goal related
to production volumes.
Identifying
basic physical operations
A system integrator
needs to quickly gain an overall understanding of the production
process to ensure that it matches the requirements. The
following allows a swift response from a potential supplier:
A clear definition of the required assembly process actions,
preferably in diagrammatic form
The allowed time to produce one part, for example,3/s
or 1/min.
A completed assembly drawing or sketch.
Component drawings with tolerances, if possible.
A description of the method of presentation of each component
part to the system, for example, loose in a box, on a
conveyor, pumped or in a tray.
Details of how the finished assemblies are to be presented
or packaged.
Requirements
for product verification
Next the requirements
for product identification and verification can be evaluated.
The extent of work in this area will depend on the cleanliness
classification and validation requirements of the production
environment. Some processes do not require verification
of component parts as they enter the automated system. Most
subcomponents that carry a drug must be uniquely identified
and this must be recorded as the unit enters the process.
More often today, parts not containing drugs must be checked
as being present using Poka Yoke techniques.Poka Yoke is
Japanese for mistake proofing that involves 100% automatic
sensing of all components individually and together to check
the assembly.1
A clear description
of how the parts can be identified and how the information
is to be logged or verified is essential to the design of
the control elements of the automated system. Automated
processes are moving to 100% traceability of the finished
parts, therefore, labeling and data-storage requirements
need to be defined and communicated to the system integrator.
The control information specifically relevant to data handling
and verification will require knowledge of automated manufacturing
practices, GAMP 4,and the requirements of the Food and Drug
Administration’s Title 21 Code of Federal Regulations,
Part 11.
The
search for the right solution
A considerable investment
in time is required to properly understand the specific
requirements and to formulate the most suitable solution.Even
with a clear route to communication between the system integrator
and the manufacturer, this can run into many months of work
for both sides just to be able to determine the correct
solution.Before a dialogue begins, it is important that
the manufacturer satisfies himself that the potential supplier
of the equipment is capable of working to the required standards.Quality
systems standards such as ISO 9001/2000 and quality system
requirements,QS 9000,are useful benchmarks for selecting
system integrators with experience in industries outside
the medical manufacturing industry.
Scope
of project expertise
When sourcing an
integrated system, manufacturers may also wish to investigate
the extent to which the system integrator performs the separate
aspects of design,manufacture and assembly in relation to
the mechanical,electrical and software/control aspects of
the project. Most manufacturers would like all of these
elements to be directly performed by permanent staff within
the system integrator’s company to ensure the timely
completion and proper support of the machine or system once
it is in service. Some system integrators subcontract major
elements of software,control panel wiring or manufactured
parts.In addition, a supplier must be able to support the
system from concept,through manufacture, assembly,capability/commissioning
and into production.
Additonal
assistance
There is no one single
route to selecting the correct system.Selection must be
on a case-by-case basis,matching the requirements of the
assembly system.In the future,there may be some assistance
in assembly system design and specification. There are currently
two research programmes in this area.The first is a European
Union thematic programme called Assembly-Net,
which is a discussion forum on assembly system design,manufacture
and use. The second is a project under the Eureka Factory
mechanism called E-Race that is just about to start. E-Race
is attempting to develop an interactive website for requirements
capture and design of flexible assembly systems
References
1 For
information on Poka Yoke: www.keyence.co.uk/topics/poka_yoke_kaizen/guide.html
