By: Hans Noack
August 25, 2010
This subject has been discussed for twenty-five years or more; which direction to choose depends on the complexity of the application and type of manufacturing one does.
The basic process of creating drawings to represent objects has been around since the days of the caveman. In the world of manufacturing, this process began with basic 2D drawings known as “blueprints” that showed three basic views of an object: Plan, Front and Side. If additional views were needed (inside, outside, isometric, etc.), each of these views had to be created separately. The designer had to first be able to visualize the whole entity in order to project each of the necessary views onto a blueprint. Others could then read the blueprint to view and understand the whole entity.
Machine operators studied blueprints and extracted the information they needed to ultimately produce a physical object that matched the views shown. They entered coordinates and determined cutter types & sizes, drill bits, taps, etc., and then began machining.
The time required to create a 2D drawing was relative to the complexity of the part or the assembly of parts. A very simple part could be four lines that create a square, and if you need some through holes in the corners you could add four circles. Notes and dimensions were added as required. Creating an assembly required multiple sketches or drawings. This could either be done by sketching on paper or using a drafting board. When multiple copies were needed for distribution, paper sketches were copied by hand using see-through paper whereas drafting board drawings could be duplicated more quickly by a blueprint machine.
Then came electronic 2D design with CAD software. This enhancement allowed a company with computer monitors throughout its facility to give everyone involved access to the drawings, making hard copy paper drawings unnecessary! Any revisions to the original CAD drawing were automatically viewed by everyone opening it on their computer. Electronic design software presented a distinct advantage because there everyone had access to the one and only “master” CAD model. When changes were made to this master model, everyone instantly had access to the update. This saved the time and expense of having to manually revise multiple copies of paper drawings.
From a manufacturing standpoint, 2D electronic data can be used to generate manufacturing programs that drive a machine tool to follow a given outline. Since it is limited to XY vectors, 2D data is sufficient for Wire EDM (Electrical Discharge Machining) and the majority of all through machining applications, holes, slots, window pockets, spline shapes.
The introduction of 3D electronic data made it possible to represent a solid object in 3 dimensions. It includes XY and Z vectors (or IJK vectors). The benefits of creating a 3D model are numerous.
Once the 3D model is created, it can be viewed by multiple people as if they were holding the physical object in their hands. It is a solid body with volume, mass, internal and external features, and it can be rotated to any viewpoint allowing you to extract the information you need. At Matrix Tooling, Inc. our designers use NX software (formerly Unigraphics).
The time required to create a 3D solid model is dependent upon its complexity, and 3D solid assemblies of multiple parts can also be created; an automobile assembly, for instance, might be used for display, sale, mechanical function, or aesthetic purposes.
The availability of 3D data has virtually eliminated the need for any 2D drawings in manufacturing, although some customers will still ask for them. It takes considerably less time to create views on a drawing using 3D data; it’s just a matter of placing canned or custom views on a drawing that are linked to the 3D solid model or assembly. The views are always to size and if a revision is made to the model, the drawing views are updated automatically.
Manufacturing using 3D data allows a machine operator or a CAM specialist to generate any type of machine path, limited only to the machine tool’s axis – be it 2D or multiple axes.
While 3D software packages are certainly more expensive than 2D systems, we have found that the benefits far outweigh the costs. In our business of designing & building complex plastic injection molds, 3D design has not only helped us become a leader but will also play a critical role in maintaining our advantage.