Design Realization/Detailed Design - Medical Device Design: Innovation from Concept to Market - page 158

Co. Name Product:

Part:

Calculations performed by: Date: Sheet:

X of Y

Description:

Assumptions:

Model / Equations:

Calculations:

Conclusions:

Signature:
Name:
Date:

Checked: (if appropriate)
Name:
Date:

Figure 8.1
Typical design calculations pro forma.

It is important that the “calculator” signs off all design calculations; they may need signing off
by someone in authority (as described earlier) so make sure a provision has been made for both.

Note that many calculations are now performed using computer models. Most industrial
systems have the capability to produce a report similar to that of Figure 8.1 . If the one you are
using does not then you must produce one yourself. It is a common failing of people using
computer models to only give a final answer; this is not enough. Programs such as MathCad®
produce a report as you build the model. Finite element packages, such as ANSYS, also have
a reporting function. The trouble with all of these is that you must include the “assumptions”
and “conclusions,” so make sure you do.

CASE STUDY 8.1
Consider a simple circuit within a blood pressure monitoring system. A simple low-pass
filter is required.

Filter Co Ltd Product: Blood Pressure Monitor

Part: Low-Pass Filter

Calculations performed by: DJC Date: 24th June 2011 Sheet: 1 of 1

Description:
A simple low-pass filter with a cutoff frequency of 400 Hz.
Assumptions:
The system will be a simple first-order filter.