Cutting & Drilling

Making Holes and Cutouts: How to Drill Holes in an Enclosure

Drilling holes in an enclosure may seem like a straightforward task, especially when working with non-metallic enclosures, which are generally more accommodating than their metal counterparts, such as stainless steel. However, to ensure optimal quality, certain techniques should be employed.

Potential Issues when Drilling a Hole in a Stahlin® Enclosure:

The primary failure modes during improper hole drilling are delaminating or chipping of the outer surface and the occurrence of melting/strings of polymer material and glass fibers directly below the surface.

Causes of Problems:

Excessive edge chipping around the cutout or hole is typically attributed to improper tools and methods. Delamination failure may occur due to a tearing action when excessive material or improperly sheared fibers are removed. Delamination can result in downstream assembly issues, functionality problems, and an unappealing appearance.

How to Ensure Clean, Smooth Drilling:

A dull cutting tool is the most common source of failure when making drilled holes. Planning and understanding proper polymer machining methods can significantly impact the final outcome. Recommended tools for hole drilling include carbide-tipped or PCD diamond-tipped hole saws, or a twist drill bit attached to an electric drill, maintaining a sharp cutting edge. High-Speed Steel (HSS) tools can work but may become dull, leading to excessive chipping. High RPMs and low feed rates are recommended, reducing chipping around the cutout. The key factor is keeping the tool sharp.

Additional Options for Drilling Holes:

Hole Saw:

1. Lay out the cutout size and location, with something like a marker or masking tape.
2. Pre-drill a small hole in the center for the hole saw to start.
3. Carefully cut out the area.
4. Although time-consuming and less accurate, it can be done in any environment. Keep the saw perpendicular, maintain a consistent sawing action, and use a diamond/carbide impregnated saw or fine-toothed saw for a high-quality cutout with minimal edge chipping.

Routing:

1. Produces clean holes and cutouts but requires manual layout.
2. Use a jig, fixture, or CNC machining centers to guide the handheld router.
3. Diamond impregnated router bits are preferred for longevity.

Punching:

1. A standard knockout punch produces clean holes but may leave chipped edges if dull.
2. Maintain sharp tools for clean cutouts.
3. A pilot hole is required before using a standard hole punch.
4. Manual or hydraulic punch actuators can be used with composite materials but are not recommended for polycarbonate.