How to CNC machine a packaging design model
Concept models and rapid tooling for pudding packagingMONA is Hollands largest manufacturer of desserts. It is a division of Campina Melkunie, a large supplier of dairy products. MONA offers various types of desserts, amongst others a complete range of puddings. One of the luxury puddings is called the Bavarois, and Mona wanted the packaging to communicate this luxury. The packaging has to look attractive on the supermarkets shelf and, after emptying, the pudding has to look attractive on the table as well.
CAD design in Rhino: wireframe and Rhino rendering.
A number of designs and design-variations have been created, using the Rhino 3D CAD software, in order to satisfy all requirements. Being a NURBS modeler, Rhino is very suited to design a complex freeform product like this bowl. The rendering shown was made using Rhino's built-in renderer, for more life-like pictures the program Flamingo is supplied.
Concept RP using DeskProto: DP screenshot and some concept models in foam.
Each of these concepts has been presented using various CAD renderings, however for a more accurate evaluation tangible prototypes were required. So a number of concept models in PUR foam have been machined using DeskProto, offering a good evaluation at low cost. The advantage of DeskProto is that rough settings can be selected, making it possible to machine a model within an hour. The cost of the foam is neglectable.
A number of solid prototypes (block models) have been milled, of different designs, using PUR (PolyURethane) foam. No finishing or smoothing with sandpaper has been applied. These concept models have been used to test the appearance of both the packaging in the supermarket and the pudding on the table. The models proved to also be very effective to present the designs to the marketing department and to management before choosing the winning design.
Machining a presentation model in two separate parts, on the same desktop machine.
Of this winning design a perfectly finished presentation model has been machined in tooling board. Again using DeskProto, however now with settings for a precise model.
This bowl model was too high to be machined on the available desktop milling machine. Also when using a larger machine the height still would have been a problem, as the required small inner radii made the use of a thin cutter needed. And obviously: the smaller the cutter's diameter, the shorter the cutter will be as well. Using DeskProto this problem is easy to overcome, by building the model in separate parts that can be stacked later. The tooling board to be used is supplied in slabs at an exact thickness, making this even easier. Slabs of 50 mm thick Cibatool were used (or 2" Renshape), with a 6 mm (diameter) ballnose for roughing and 3 mm ballnose for finishing.
Before final approval of the design also a test series of bowls had to be manufactured on the actual production machine of the packaging factory. To create a 'soft-tool' for this test the presentation model has been used. The mold was made by casting an epoxy resin over this model. The bowls that were manufactured this way have been filled on MONA's pudding production line for a final test.
The styling block model 0f this "family Bavarois" bowl, together with the resulting product.
The final production bowls are made in polystyrene. As the product is 'packaging only' you can buy this fine design at very low cost (in the Netherlands only).