A Basic Design Process

The process of designing and selling components can vary widely depending on multiple factors, such as industry, manufacturing capabilities, part or system complexity, and regulations. Our company specializes in custom 3D printed parts. Thankfully, in many cases of custom-designed or unique 3D printed parts, capabilities exist. Another benefit of custom 3D part manufacturing is that, generally speaking, there is not much regulation. Whether you need to redesign an existing part to meet your needs better than a traditionally manufactured part, or you want to create an entirely new part, 3Dprinting can help you accomplish these goals. To demonstrate what goes into the design process when 3D printing a part, we will explain the basic processes we used when designing a drill fixture for a GPz550 motorcycle cylinder head.

This tool we are discussing, which is an original part designed by ECA, is designed to help an owner or machinist properly and accurately locate a drill bit in order to drill out stripped threads in a 550 motorcycle cylinder head. When designing a part, always start by meeting your core requirements, and remember that everything else is a bonus. For this tool, there the tool had two primary functions – to precisely locate the position of the hole to be repaired with respect to other known locations, and to hold the drill bit straight up and down (while in position) to allow a clean, straight drilled hole.

Measuring outside dimension of dowels

With that in mind, there were 2 main issues that we needed to settle before we could manufacture the part. First, we needed to determine the exact location of the hole with respect to other features. Second, we needed to size the tool to accurately locate itself on existing features. In this case, there are groupings of 4 holes, which are used to retain two camshaft caps. These holes also contain alignment dowels, which are used to position each camshaft cap. We started by measuring the outer diameter (OD) of each alignment dowel. Next, we used calipers to measure the outer edge of one dowel to another. After that, we can subtract the dowel diameter to get hole spacing in both the X and Y dimensions.  This sets up the basic size of the tool.  The dowel OD is used to size the holes in the part so that the tool aligns properly on each dowel pin.

Test print to verify spacing

At this point in the process, we used CAD software to design a very basic rectangle with 4 holes.  We printed this part only 6mm thick in order to use it as a sizing guide.  The X-cross brace in the part provides rigidity in all directions.  This part also could have been one big brick, or we could have carried the 3 rectangular cutouts from the sizing test piece into the final. However, we chose to remove the three rectangular areas simply as a way to save print time & print material.  


Final Drill Guide

After checking that we had proper X, Y hole location and snug (but not too tight) fit on the dowels, we were sure that we understood the location of each hole.  This was the most critical aspect of this particular part.  Alignment of a drill bit comes quite naturally on a 3D printed part because the hole is formed as a cylinder perpendicular to the build plate. We size the alignment hole to fit drill bushings, which are pressed in from the top and the bottom.  Since they guide themselves into the hole and we use a two sided press, we can be assured that they are axially aligned with one another, but we always check with a properly sized drill bit to be sure.


           Now that we have walked you through the design process for our GPz550 motorcycle head drill fixture, hopefully you feel that you have gained insight into how we can create a custom part. Utilizing3D printing gives us, as the manufacturer, the opportunity to work with clients to create parts that meet their exact specifications and needs. Somebody’s need for a custom part may vary – maybe traditional parts do not fit correctly, the part you need is discontinued or hard to find, or you have an idea for part that does not exist yet. Whatever it is, we can work with you to design the product that you have in mind.


 -Mike Z




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