Wanting to know what would be the best way to make the 200+ holes? Can you use a .25" upcut end mill and “drill” all the holes?
A drill is ~4 times better going down than across. An end mill is ~4 times better going across than down.
Drilling with an end mill is commonly called a “plunge”. Although an end mill is relatively inefficient for drilling (compared to a drill) it is often the best choice when one does not have an automatic tool changer. The time to change the tool weighs the time to drill a few holes.
With a large number of holes - time wise - it makes sense to switch to a drill as things will overall be faster. That said, many people appreciate minimal tool changes and will accept the extra time to complete a job.
Depending on the end mill diameter and material, one commonly doesn’t plunge all in one go. One has the CAM software generate multiple operations that accumulate to the requested depth (often called layers).
The general guideline for plunges is no more than 1/2 the diameter of the end mill per layer. Often, one has to do a bit less because of the nature of the stock (material).
To learn about end mills please see:
Many CAM packages are fussy about their holes. Some packages will allow a 0.25" end mill to make a 0.25" hole, others require a smaller end mill or making the hole 0.251". I’m not a Fusion user so I can’t speak to how it behaves specifically.
If one can use a 0.25" end mill for 0.25" or 0.251" hole, be sure to use “peck drilling”. The end mill will occasionally withdraw, removing most of the accumulated material in the hole.
Smaller diameter end mills will cause the CAM software to generate not only layers but also a pattern to remove all of the material in a larger hole (a “pocket”).
The highest volume end mills are 0.125", 0.25", 0.5", 0.75", 1.0" and so forth. Yes, there are odd sizes but these tend to cost more (low volume) and be harder to find.
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