Ben Richardson: 3D Engineering Projects Solved in 2D AutoCAD

Ben Richardson is the Founder of Acuity Training Institute. He has been teaching students AutoCAD for over 15 years. Ben reached out to me about guest posting on It's Alive in the Lab. I was happy to accept his offer.

Founded in 2002, the Acuity Training Institute is focused on building long-term business relationships by offering high quality, interactive training. Acuity is located at the Surrey Technology Centre in Guildford, UK which is about 30 miles outside of London. Each of their training rooms is equipped with modern PCs and LCD displays, comfortable desks, chairs and large wall mounted LCD displays to allow trainers to demonstrate to students how to use the software and walk them through exercises and examples. AutoCAD is one of their most popular training requests.


3D Engineering Projects Solved in 2D AutoCAD

It isn't always necessary to buy the latest 3D solid modeling software for mechanical engineering industrial design projects. In fact, it is entirely possible to design industrial mechanical components, mechanisms, assemblies, and complete and complex machines, all using 2D AutoCAD.

A few years ago, a general discussion was taking place regarding a major structural engineering subassembly, which formed part of a larger machine's design. One of the lead engineers was admiring the complexity of it and proclaimed, "That [sub assembly] could not be designed using 2D CAD," and others in the group agreed with him.

So it was explained to the group that it could, in fact, be done using a 2D CAD software package. Still not able to convince them, my final words on the matter were, "How do you think these types of structures were designed before the advent of 3D solid modeling software?"

The issue engineers can face is, too many people want to see a "pretty picture" in 3D with brilliant rendering. Whilst a 3D solid model will help with the visual presentation of a concept, it does not necessarily mean that the design will function better than a one created using 2D drawing software.

Let us consider an example of how a real life, spatially complex mechanical engineering design task can be solved using 2D AutoCAD. In the process, readers should be inspired with confidence to tackle their own 3D design tasks using 2D AutoCAD when the situation allows. A software package can be very powerful, easy to use, cost-effective, and capable of complex tasks if you have the knowledge and motivation to try it.

The example involves the design of a one-off special purpose automation machine that was required to automatically assemble several components together and then pressure test them. The components were part of an engine cooling pipework system. Referring to Figure 1 Main Tube, it can be seen that, the main tube axis is rotated or angled in both the x and y-axes.

Figure1
Figure 1 Main Tube

The specific 3D problem to be overcome, involved the clamping of the Main Tube to permit accurate alignment and assembly into the mating part.

Since precision would be the key to success, a close examination of the physical components to be assembled was required, by measuring them accurately, checking the dimensions against the manufacturing drawings, and finally drawing them into AutoCAD using first angle projection, (front elevation, end elevation, and plan view), the associated components could be added around them.

A pneumatic cylinder would be used to clamp and release the Main Tube, utilizing a machined aluminum block secured to the cylinder rod attachment using socket head cap screws. The opposing face of this block was required to match the Main Tube surface diameter, plus a very small clearance allowance so as not to pinch and therefore mark or damage the tube.

This was accomplished by machining a concave feature into the aluminum block whose axis aligned with the Main Tube component. The technique used was to match the mating surface profile and then reposition the block in the x and y-axes, by the same distances the tube axis was offset. Additionally, by splitting the interfacing machined aluminum block between the pneumatic cylinder rod attachment and the Main Tube, into two individual machined parts, namely the Tube Clamp and the Tube Spacer. See Figure 2 Design Elements & Figure 3 Tube Clamp & Figure 4 Tube Spacer.

Figure2
Figure 2 Design Elements

This allowed each part to be simpler in design and therefore easier to manufacture than one single complex part. Manufacturing costs should also be lower. This would be true even if a 3D solid modeling software package was used.

The Tube Clamp was designed to perform the clamping of the Main Tube, whilst the Tube Spacer would connect to the Tube Clamp and position it at the correct orientation relative to the pneumatic cylinder.

Figure3
Figure 3 Tube Clamp

Figure4
Figure 4 Tube Spacer

The same principle was applied to the lower support of the Main Tube with the creation of the Tube Support and the Tube Positioner.

Figure5
Figure 5 Plan View — Shows the Tube Clamp and the Tube Spacer orientation relative to each other and the Main Tube.

Each design project is unique and will have specific problems to be solved. However, a general approach to assist readers would include:

  • Ensure accurate recreation of the parts involved using first angle projection drawing views.

  • Look for ways to reduce the complexity of the task or the components, by splitting into simpler ones.

  • Allow adjustment in the appropriate components for fine-tuning their positions on final assembly, if required.

Whilst 3D solid modeling software is a more comprehensive package, which is well suited to highly-complex surfaces such as those seen in elaborately designed consumer products, its price may be prohibitive for some individuals and businesses. In addition, many industrial mechanical engineering disciplines do not consider aesthetics to be a prime objective. Factors which are much more important are function, strength, low cost, ease of manufacturing and assembly, and maintenance in service. These come from the engineer, not the software tool.


Thanks, Ben.

One less dimension is alive in the lab.