Wednesday, 4 February 2015

SOLIDWORKS DFMXpress – Drilled Hole Checks Overview

SOLIDWORKS DFMXpress – Drilled Hole Checks Overview

Designing is a crucial stage in a product’s life cycle. It is very important to detect and eliminate errors in the initial stages of design, since these errors will cause problems during manufacturing or increase production costs.

How good will it be, if SOLIDWORKS has an automated manufacturability validation tool?(DESIGN FOR MANUFACTURING)

The answer is Yes.

DFMXpress is an analysis tool that validates the manufacturability of parts. It helps in upstream validation of areas, which are difficult and expensive to manufacture. It also provides a mechanism for knowledge captures and employ for continuous betterment.

DFMXpress functionality includes:
  • Drilled hole checks
  • Milled feature checks
  • Turned part checks
  • Sheet metal checks
  • Standard hole size checks
  • Injection molding checks


In order to reduce tooling costs and for efficient manufacturing, there is a set of rules, to be followed, which the above functionalities carry.

Drill rules:

  1. Hole diameter-to-depth ratio: For production, small diameter holes (less than 3.0 mm) and high depth-to-diameter ratios (greater than 2.75) are difficult and not recommended. Deeper, blind holes make chip removal difficult
  1. Flat bottoms on holes: Blind holes should not be flat bottomed. While reaming, flat-bottomed holes cause problems. Standard twist drills should be used to generate cone-bottomed holes. The bottom angle should conform to the angle on standard drills
  1. Perpendicular entry surfaces: The entry and exit surfaces of a drilled hole should be perpendicular to the hole axis. The drill tip might wander if the surface, which the tip contacts is not perpendicular to the drill axis. Exit burrs will be uneven around the circumference of the exit hole, which can make burr removal difficult
  1. Holes that intersect internal cavities: Drilled holes should not intersect cavities. During machining, drills follow the path of least resistance when intersecting a cavity. The drill might wander when it reenters the material. If a hole must intersect a cavity, the drill axis should be outside the cavity
  1. Partial holes: When a hole intersects a feature edge, at least 75% of the hole area should be within the material. Do not let the axis of the hole intersect an edge of the part or the drill might wander
  1. Tolerance checks: Tolerances should be no tighter than necessary. Stringent tolerances might require special process parameters that are not within the natural capability of available machine tools
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