Reverse Engineering/Product teardown

Holmes: "Then there is the curious incident of the dog in the nighttime".

Inspector Gregory: "The dog did nothing in the night-time".

Holmes: "That was the curious incident."

Reverse engineering requires the intellectual skills of a fictional detective. These include gathering together facts, deducing information from the facts and inferring what is not obvious. Reverse engineering begins with the product and works through the design process in the opposite direction to arrive at a product definition statement (PDS) but in doing so should uncover much about the design ideas that were used to product a particular product (figure 1). This technique produces information about the product that relates to its manufacture, reliability, cost, functionality, etc. Reverse engineering can be either as a systematic approach to studying the design process OR as an initial step of the redesign process: Reasons for reverse engineering a product

The original manufacturer of a product no longer produces a product or no longer exists and a customer is tied into that product.
The original design documentation has been lost or that documentation never existed.
Clever and innovative aspects of an old product were never recorded in the design documentation and a similar product is to be designed.
Poor features of a predecessor product were never recorded in the design documentation or only became apparent once the customers started using the product. You feel these bad features should be designed out.
Long term use of the old product illustrates strengths and weaknesses of a design. For example excessive wear might indicate where a product should be improved
You wish to analyse the good and bad features of your competitors rival product. Reverse engineering is very common in software engineering, and less common in chip design, electronic design, mechanical designs and mechatronics.

Design flow. Left: Generating a useful product from an idea. Right: Generating new knowledge by reverse engineering a useful product.

Questions to be asked of a reverse engineering exercise

How does it function, what are the weaknesses and strengths, how could it be improved?
Is it Non-destructive/destructive?
How can cost be reduced and performance increase?
What auxiliary sources of information are available e.g. Similar products/technical specs?

Intellectual property/Ethics

Copying verbatim without acknowledgement or permission is intellectual property theft

Imitation is a sincere form of flattery.

Products can be protected from copying by either copyright or patents. Patents protect the idea(s) behind the functioning of a new item whereas copyright only protects the look and shape, consequently a patent is a stronger protection against copying. Often however a patent is no more than a warning sign to a competitor, a claim to pin to a product to put off competition. If there is merit in the idea a competitor will either a) negotiate a license to use the idea, b) claim that the idea is not novel and is an obvious step to anyone practised in the field or c) will make a subtle change and claim that this no longer comes under the patent.

A famous chemical company used technique c) to defeat a patent on a manufacturing process.
Bridge and building designs in civil engineering tend to be copied from past successes so their is less chance of catastrophic failure.
In Computer Programming, good source code is often a variation of other good source code, e.g. numerical recipes, structure for linked lists.

Reverse engineering levels

Decide between destructive and nondestructive reverse engineering The general principles can be applied both to the system in operation, or to the individual sub systems.

Factual stage

Determine organizational or customer needs
Preliminary analysis
Highlight possible difficulties in disassembly and reassembly
Plan product disassembly
List disassembly steps so reassembly is possible.
Identify any third party subsystem sources (e.g. electric motors, chips)
List subsystems and parts.
Identify individual subsystems and how they function
Identify material and manufacturing process
List of sensors
List of actuators

Deductive stage

Determine overall function and subsystem function
Develop black box model showing materials, energy and information flow into and out of the product
Identify actual physical principles
Identify the physical principles (conservation of energy, etc) that apply to the product
Identify how subsystems interact

Inductive stage

Predict how the product might work
Estimate costs
Hypothesise manufacturing processes

New solution concepts

Identify component features that make it a success, e.g. light weight, strength, manufacturing costs.
Use new information in new ways
Depending on the intent of the RE purpose, document how costs can be reduced, functionality enhanced, the intellectual property used in other designs, the good and bad features, produce a likely product definition statement.

The new PDS might also identify areas where the product could be modified, either in design or in manufacture, might identify any special purpose or labour intensive machining required.

Note on costs

Estimating costs can be difficult. A complex part made in large numbers will be relatively cheap (e.g. components in a disc drive, whereas a short run of 10 items will require a lot of hand machining where the primary cost is that of a skilled machinist. Other costs that contribute to shelf price are the cost of assembly, packaging, technical support costs, user and technical manuals.

Black box system analysis

Considers flow across a boundary set up around a system or subsystem,

Material

Any matter that crosses the system boundary Information
Might include information from sensors
Energy is conserved so energy flow in + energy stored = energy flow out
Power = dE/dt
Primary energy 'lost' is via heat, but might also be lost as EM fields.

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