In a nutshell, digital modeling is one of production power tools that come out of using a 3D CNC system to produce concrete molds. Once the initial model has been agreed upon, it is scanned by a 3D scanner and a digital version is automatically created. This fully interactive digital model replaces a host of onerous manual planning techniques by providing the means to refine, alter, replicate, and fabricate molds far more quickly and cheaply than has ever been possible before. The digital scan can be used in a number of ways: you might, for example, want to produce a mold that will exactly replicate the model or maquette used. Such a production plan will require little digital modeling on your part, because the software associated with your 3D scanner will do all the work. It will automatically generate all the tool path data required for the CNC 3D router and it will automatically turn the scan from a positive to a negative (or vice versa), generating the data required to carve a mold of the object. Thus, creating the mold becomes a matter of simply uploading the original scan file to the CNC router. Another scenario might have a more extensive digital modeling stage. This occurs when you want to make changes to the 3D digital version that the scan has generated. Perhaps the client decides that they would like to add or remove features, or that they want to change the scale, the depth of a cut or basically anything that they (or you) can think of. Rather than producing a new physical model, all these changes can be done digitally, and the client can view a full, 3D digital version of the planned work without the need for further physical models and also with the confidence that the finished project will be an exact match to the digital model. In either scenario, digital planning provides for a substantially faster time from concept to production and a more effective communication strategy than has been previously available.
When using a digital model, mold fabrication is quick and easy for even the most complex and organic shapes, because production can be almost totally automated. The 3D digital file of the mold is uploaded to the 3D CNC router and the router will automatically carve the mold. Depending on the size of the mold it might be carved out of a single block of material or it might take several blocks, the pieces of which will need to be assembled together. Either way, the 3D modeling software will have calculated the most efficient use of materials and will indicate how to do this. Once the form has been carved it can either be sprayed with a protective coating and used as the actual mold or plug, or another mold material, such as GRFC, can be applied and the mold taken from that. Depending on the requirements of the mold and the finished project (such as mold reuse, concrete smoothness, and budget) one option will be a better solution for that particular project. Because the router is working off of tool paths generated by the 3D scan of the model, the mold it produces will be an exact replica of the model and will require very little in the way of rework or alterations prior to use. (It also ensures exact repeatability. As long as you have the digital file you can produce that exact mold as often as required, without the need for keeping a large mold inventory.) Therefore, creating the mold is a very quick and simple process and one that require almost no manual labor. In fact, many shops run their 3D CNC routers overnight, returning to finished molds in the morning.
When using modern mold making techniques you can further increase production speeds by better managing the nature of the model itself. With a maquette intended for 3D scanning there are several key things to consider that can impact overall production speeds. Firstly, the size of the maquette is irrelevant to the size of the finished mold, because 3D software can automatically enlarge or reduce the file as needed before production in order to achieve the required dimensions. Avoid wasting money and time on the production of large-scale models. If for some reason a full-scale model is required, it is much faster and cheaper to scan the small maquette and quickly make a foam prototype on the router. Secondly, the quality of the maquette is important. The better the maquette is the better the mold that it will ultimately produce. Good 3D scanners will capture an object right down to minute surface texture and good routers will produce it. You can save time during the finishing stage if the original scanned model is without flaws that need digitally or manually repaired. Lastly, as most models are significantly smaller than the finished project or piece, keep in mind the impact of enlargement on features and details. You may want to have more or less depth within 3D features of the maquette depending on the finished intent.
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