3D Modeling & CAD for Motorsport: Design for Manufacturing
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Design for Manufacturing
06.36
| 00:00 | As you get more proficient with CAD, you'll be able to model some very complex and creative designs. |
| 00:05 | Taking inspiration from the top levels of motorsport like F1, LeMans prototypes or even trophy trucks. |
| 00:12 | Once you get to this point, it becomes very important to understand how your designs will be manufactured from the materials you specify. |
| 00:20 | It's all very well designing an intricate bracket with undercuts and pockets to shave weight but if you only have access to a simple 3-axis mill there's a good chance it's not even possible to make the part. |
| 00:33 | This is why it's crucial to understand the manufacturing method before we start the design, as well as the costs involved with materials and the manufacturing process. |
| 00:42 | Otherwise, we're likely to end up with designs that are extremely expensive or just impossible to produce. |
| 00:48 | Depending on the design, material and the intended use there could be multiple options for the manufacturing processes available. |
| 00:56 | If that's the case, we'll need to weigh up the advantages and disadvantages of each process and find what makes the most sense for our situation. |
| 01:04 | Once this is decided we can spend some time getting familiar with the manufacturing method and understanding what's involved to turn the raw material into the completed component. |
| 01:13 | When bringing CAD models to life, some common manufacturing methods. |
| 01:18 | we see are water jet or laser cutting for sheet metal jobs, While milling machines and lathes are commonly used for billet aluminium components, as well as your general fabrication techniques, like cutting, drilling, grinding and welding, it's not uncommon to see parts made with any combination of these techniques. |
| 01:36 | 3D printing has also become accessible down to a grassroots level in the recent years and can be used for prototyping and producing final parts. |
| 01:45 | There of course many more processes out there like forging for performance wheels, laying up carbon fibre body panels or injection moulding plastic parts, all of which can involve the component being initially modelled in CAD. |
| 01:59 | We're unlikely to be using these methods as enthusiasts though, as it requires some serious financial backing from a professional environment. |
| 02:07 | When designing we need to keep in mind the limitations of the manufacturing method. |
| 02:12 | For example, let's look at a sheet metal component with bends. |
| 02:16 | We need to consider if the laser cutter can cut the material thickness we require and if the folder we plan on using can also bend this thickness. |
| 02:25 | A common mistake when designing parts with multiple bends is not accounting for the actual bending process and designing a part where not all bends can be made in the folder. |
| 02:35 | For example, while it's pretty simple to model this part in CAD, when we try to fold it up, we can see that the geometry doesn't allow us to make the intended folds using the equipment we have available, because part of the component hits the folder before we achieve the desired fold angle, preventing it from being folded further. |
| 02:54 | It's important to be sure we can achieve all the bends before we get the part cut and know the order that the bends need to be made in. |
| 03:02 | If it's just not possible with the equipment available, compromises need to be made in the design. |
| 03:07 | if we're sending our design in the form of technical drawings or exported CAD files to another party to be manufactured, t's best to talk to them about the manufacturing process before the design is finalized so we can understand any limitations, special considerations and generally what they'll need to produce the final piece. |
| 03:26 | With any manufacturing process, no matter how advanced, complicated or expensive, the accuracy is never going to be perfect and and we need to consider the tolerances of the finished component. |
| 03:37 | In some cases, this might not be so important as the dimensional accuracy won't have any impact on the functionality of the part, but for any part that interfaces with others as an assembly or the dimensions are key to the part's functionality, we have to account for potential discrepancies between the nominal and actual dimensions. |
| 03:57 | The more processes involved the more chances there are to introduce variance. |
| 04:02 | To illustrate this let's look at a quick example. |
| 04:05 | Here is a simple sheet metal part with two holes. |
| 04:08 | There's inevitably going to be some variation in the distance between the holes in the final piece compared to what we specified. |
| 04:16 | And adding a bend in between is only going to introduce more variance. |
| 04:21 | This might not be an issue by itself, but if this part needs to fit with another part we've also designed that also has variance, it's very easy to see how these can stack up and cause problems. |
| 04:31 | Again, talking to the manufacturer or tooling operator to understand the expected variation that we could see in a part like this would be a very good idea. |
| 04:40 | In a mass production or professional environment, it's very common to complete what's called a tolerance stack analysis, or review measurements from sample batches before the design is finalised. |
| 04:51 | This isn't necessary in our case, we just need to understand that these discrepancies exist and to what magnitude we can expect. |
| 04:59 | Then with some critical thinking, we can design our part to minimize or avoid these issues. |
| 05:04 | For example, using slotted holes where possible can quickly reduce the risk of fitment issues. |
| 05:10 | Adding features to indicate bend line positions or self-jigging features for welded parts can also reduce measurement and set up errors. |
| 05:19 | An extension of what we're discussing in this module is what's called design for assembly, which is as it sounds. |
| 05:27 | As with the example we just looked at, the tolerances of interfacing parts need to be considered, so when it comes time to assemble them together, we can be sure they'll fit and function as intended. |
| 05:38 | This can come down to making sure the holes line up properly and that there's no unwanted interference, Or that the actual type of fit, whether that's clearance, transition or interference is as we specified. |
| 05:52 | In summary, the most important takeaway from this module is that we need to understand the manufacturing process we intend to use and how its limitations will affect our design. |
| 06:02 | Different manufacturing processes and materials present new sets of considerations and there are advantages and disadvantages to all of them. |
| 06:10 | We want to design high quality parts that look good and perform well, while avoiding making them extremely difficult expensive or even impossible to manufacture. |
| 06:21 | With every manufacturing process there will be discrepancies between our nominal dimensions and actual dimensions of the final part. |
| 06:28 | Failing to account for these in the design phase can cause fit and function issues down the track. |
