Pondering the Design

traction engine tender on the mantelpiece

Sometimes it is good to just ponder the design. This allows your brain to bring together the different elements of the design. Look at conflicts in the design, check the aesthetics. Even trade certain design features and their impact on the total system of parts. Pondering the design is especially useful if you are designing the part on your own.

Gateways

In commercial design it would be normal to use gateways where you can review the design against a number of criteria. This allows a team to assess fully the technical design, business and manufacturing. This allows the review to take into account the delivery, cost, robustness, virtual capability as determined by detailed multi-physics CAE models and the simple design elements review.

However, this requires a number of people with a broad range of skills. This allows the design to progress rapidly and in a robust way.

Sole Designers

The problem with working alone is how do you get the design critiqued? This is where I think the mantelpiece comes into it’s own. What I mean is just stopping, placing the part on the side and staring at it for at least a few hours. Even better is to place it in the room where you relax, then at some point you will ponder the design and wonder about alternatives.

You can post the design, if it’s not commercially sensitive, onto online forums. For the model engineering items I make I often post onto Model Engineer or HMEM. The online care point is that you need to ready for comments that might not always be that useful. They might even be very harsh. However, mostly on the model engineering forums they are kind and very helpful.

Example

My example is the water tank for my 1/20th scale Burrell traction engine.

water tank in tender

My original design was to create the water tank with the outside of the tender and a plate (seen in photo with blue marker on upper surface) that also forms the floor of the tender where the driver would stand.

However, this means the tank is structural and sealed. Also, the water pump will be difficult to fit afterwards. This gives me a lot of design and build elements that have to go right first time. This is difficult and risky.

So, I sat pondering the design with the part on the mantelpiece. I also posted an image online.

 

The online comments didn’t give me the improved design, but they made me think. A comment mentioned the common floor and top of the tank and that this could be masked. 

Hence I started thinking about making a separate tank. All of a sudden this made the design free of a number of constraints. The floor could now be removable with a few bolts and then it could extend further forwards. This would then allow me to checker plate the top surface of the brass and create a sealed and tested water tank that no longer had any real structural requirements.

So, pondering the design is a great tool for the sole designer and thanks to Roger for the online comment.

About Nigel 380 Articles
I've been making models since I was around 7 years old and using a lathe from the age of 11, a self taught engineer with a passion for making model engines.

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