Tag Archives: CNC mill

Tent Models as Sales Tool

Recently KiwiMill was asked to make a series of tent models to depict a manufacturer’s product line. The models would be used as a sales and marketing tool, with possible trade show use as well.

Masters were formed on the CNC mill out of tooling board to represent three different tent designs. The tents all have metal frames with wire cross pieces and the idea was to show some of this detail on the model surfaces.

The tents were then vacuum formed using the 3 carved masters. Twenty of one design were made, and 10 each of the two other designs.

Tent connectors were made from stamped sheet metal. Five different styles were built. These connectors would attach to the tents by the placement of magnets in each tent. The idea was to offer the ability to reconfigure the tents and connectors into different layouts as needed.

Vinyl graphics were digitally printed and the tents and connectors were painted olive drab.

An oak trimmed  48″ by 60″ base was constructed with sheet metal underneath a grass mat. This way the magnetized tents would stay in place when configured, rather than slipping around.

The finished diorama can be added to, subtracted from and reconfigured using different tents and connectors.

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New Fabrication Choices for Model Makers

scale model parts

With the addition of  3D printer technology, new in-house model fabrication options are available to model makers. Decisions need to be made about what fabrication method is best for building each model part. What parts should be printed, molded, CNC milled/laser cut, or created by hand? The use of all available technologies in the correct circumstances makes for an efficient, bustling shop, and quality model production. That’s the goal. Not to replace craftsmanship with machines, or to unnecessarily complicate the model building process with flashy new equipment.

Factors that need to be considered when determining fabrication method include; time, cost, accuracy of part, material being used, model type/usage,and the information available on the item being built.

The time constraints of any given project are a major consideration when determining what fabrication method to use to create a model, or its parts. Deadlines are often very tight and sometimes the initial decision to bid on a project will be influenced by how quickly it is needed and whether or not available fabrication methods (and resources) will get the model done on time. An automated machine like a CNC mill or laser may actually take longer to produce a part than hand building, but will use up less human resources in the process. How much available time needs to be balanced with the number of model makers assigned to the project and the length of time each part will take to be made using a particular method of construction.

Costs are often closely tied into time when determining what fabrication methods will be chosen. Time means money, and the amount of labour put into the job is a large part of any model price. Machines can make up for some of the costs in human labour, provided the money is there to buy and run the machine in the first place. Material costs for particular machines, such as the resin needed in a 3D printer, need to be taken into consideration as well.

Model makers need to determine how accurate a part needs to be on the model when deciding fabrication methods. Computer-programmed machining is more consistent and precise than hand building a part. This may or may not be a consideration in a given project. Sometimes a model is an artistic representation of an object, and extreme fidelity to the original design is unnecessary and unwanted.

The kind of material being used in the model will help drive the fabrication method. A 3D printer uses resin. A CNC mill can carve plastic, foam, steel, brass, wood or machinist board. A hand-made part can be rendered out of just about any material available to the model maker. Usually the type of model determines the material being used, and is determined by the model maker,  but occasionally the client will have a particular material request as well.

The type of model needed is one of the overriding factors when deciding on fabrication methods. What shape, size and quantity the model will be, as well as its purpose – display, trade show, instruction, sales or prototyping – influence the type of material used to create the model, as well as fabrication choices.

Depending on its shape, a model might be made through a subtractive method of taking away material such as a CNC mill,  while other shapes are more suited for an additive method of “growing” a part on a 3D printer. A milled part on the CNC machine needs to be flat on the bottom, no shape can be created underneath the part. This is not a problem with the 3D printer.  A completely flat part with an intricate design can be  cut on a CNC laser.

The over all scale, or size, of the model may rule out certain fabrication methods. Large parts need to be able to fit on the particular machine being utilized. The quantity of models required influences the construction. Multiple models of the same object can be well suited for mold making. A master model part is made and molded, then multiples are cast from the mold. Automated (CNC) machines in general are helpful for multiples due to their consistency over a hand-built part.

Intended model use will help establish what construction methods are used as well. If a model is going to be moved around frequently, such as trade show use,  durability and strength become important factors. This will affect materials used, fabrication, and even assembly methods to ensure a model that will stand up to repeated transport and handling. While a display model permanently housed in a protective glass case can be made of more delicate materials and finer fabrication methods, such as hand-building.

Finally, the information available to build the model will help ascertain the best fabrication method to use. If 3D files are available of the item to be built, that will lend itself better to CNC or 3D printing processes. If the model maker has only a picture or photograph to go by, it will likely be more efficient to build the model by hand, using a well-trained eye, than to try to draw the parts first in a computer program.

A well equipped model shop with a full complement of fabrication methods makes a model maker’s job more effective. Multiple factors are taken into consideration when determining which construction methods to use on any given project. Time constraints, costs, accuracy required, materials used, type of model, and information available about the item to be built all can influence this decision. Many of these factors are intertwined. Ultimately it is a model maker’s job to assess these options early on in the project and plan fabrication methods accordingly.

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Production Processes for Multiple Scale Models

Custom scale models are often one time only builds. Model makers are given an object, picture or design, they draw up the parts in 3D and set about constructing the item. Whether the finished product ends up in a museum, sales office, board room or trade show booth, it is often a one-of-a-kind model that won’t be repeated.

Occasionally, though, a model shop is given as assignment to make multiple scale models of the same design. Sometimes these are requested all at once, and other times a model shop will repeat models on an as-needed basis.

It is these types of projects that turn the model shop into a temporary production facility of sorts. A systematic approach is developed to create multiple parts in an efficient, orderly fashion. Using fabrication techniques such as casting, CNC milling, 3D printing and lasering, multiples of the same part are created.

When it comes time to assemble parts for duplicate models, jigs are designed. A jig is a tool used to control the location or motion of another tool. The jig’s primary purpose is to provide repeatability, consistency and efficiency.

Creating multiple scale models of the same object requires certain upfront approaches that would be unnecessary for a one-time build. Duplicate models are still custom-built, but fabrication techniques and production processes are controlled and streamlined in order to create a consistent product, over and over, in a reasonable time-frame.

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