What is the definition of Deep Hole manufacturing

[allenchu]

As I know, the term of Deep Hole Manufacturing is according to the ratio of the Diameter and the length of the hole to be manufactured. If the actual ratio value is smaller, then it can be named as Deep Hole manufacturing but a common machining or drilling.

I can’t remember this ration value. Anyone can tell me what the ratio value is?

 

[unclesyd]

There are numerous parameters that go into hole making with the L/D being one. You have to consider many others in the holes making process, such as material and condition, production speed, machines, tooling and others.

Here are two sites that have information on deep hole making. The Technidrill site mentions an L/D of 3-5 where one enters the realm of deep hole making. With the design of some modern machinery and tooling I consider this number to be conservative. In our in house manufacturing we used L/D's of 10-12 as a point where consideration was give to the mechanics of hole making.

http://www.technidrillsystems.com/faq.htm

http://www.ceaserver.com/show.php?&page=botek

Some of the drilling of large L/D holes can be overcome with special drills that can accomplish the job without resorting to a gundrill. We use special drills to make holes with an L/D of 12-18 in the precipitation hardening SS. One of the give aways in using something other than a gun drill is the loss of production.

Here is a link to a 30x drill. You will note in the article that there is a giveaway in that it requires a pilot hole.

http://www.manufacturingtalk.com/news/wnt/wnt178.html