Drawing creation

This blog is translated from German with DeepL.

DRAWING CREATION

Nowadays, manufacturing data of parts are often exchanged using neutral formats such as STEP, PARASOLID, etc.. However, with these formats it is not possible to transmit manufacturing relevant parameters such as material, surface finish, tolerances and the like. Therefore, most designers still resort to the well-tried 2D drawing to close this gap. This article explains a procedure to create a manufacturing drawing as efficiently and error-free as possible. Before you start creating a manufacturing drawing, remember the following:

  • As accurate as necessary, as generous as possible.
    1st priority: function, 2nd priority: production, 3rd priority: inspection
  • A technical drawing is an official document. Therefore, make sure that the information is correct.
  • Drawings often leave the company to the outside (to suppliers, customers) and represent to a certain extent the quality of your work – therefore exact and clean work is important.

 

Step 1: Model 3D part
Model the 3D part completely (with radii, bevels, etc.)

Step 2: Place views
Pick the main view of the part. Basically, the main view is the view where I can see and dimension most of the geometry elements. The mounting position is not important for the single part drawing. ATTENTION: Rotationally symmetric parts are always drawn “lying” and with the main machining side on the right (like the first clamping in the lathe).

Starting from this main view, you can place all other necessary views (using projection method 1 or arrow method). Since it is often difficult to place all views correctly right at the beginning, it is okay to add further views later.

Step 3: Functional masses

Functional dimensions are those dimensions that have a direct influence on the function of the part; e.g. diameter of a bearing seat. It does not matter whether these dimensions are practical for manufacturing or for testing the part. Furthermore, care must be taken to also set the respective tolerances and surface specifications in this step, because otherwise they are often forgotten.

Step 4: Completely measure “standard geometry

In this step, you measure all geometries that are standardized in some way. This includes undercuts, screw counterbores, O-ring recesses, retaining ring recesses, etc. Pay attention to tolerances and surface specifications.

Step 5: Set the finishing material

Next, measure all the elements that still need to be processed. This includes chamfers, fillets, cutouts and the like. Make sure that the dimensioning is optimized for production.

Step 6: Set remaining mass


Now all the remaining masses are set. This includes unmachined outer dimensions and auxiliary mass. Make sure that the dimensions are easy to measure. You can use this opportunity to check the production dimensions and the remaining dimensions to ensure that the tolerances are set as generously as possible. Do not be afraid to set a tolerance for certain dimensions that is larger than the general tolerance. It will make your part cheaper!

Step 7: Further production-relevant information


This step is important for all information which is often forgotten. Here are some examples: Hardness specifications, knurling, punching direction, mold separation, surface treatments.

Step 8: Further information

You have almost done it! The only things missing are: general surface specifications, general edge specifications ISO-3D view, general tolerances and further standards to be observed.

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