Cannulated Bar Stock: How To Solve The Biggest Problems

Odds are if you are reading this, then you are all too familiar with the pros and cons of cannulated bar stock.  It can be a great option for when you need to machine a short run of parts that have a small deep hole on center, like a bone screw or surgical instrument.  You don't have to worry about engineering a repeatable and cost effective drilling process on your swiss lathe or gun drilling machine.  Just order the appropriately sized bar with the hole already formed and you avoid all the hassle.  But what happens when you need to move into production, or if you are a contract manfuacturer and your customer bids out the larger volume contract to get the best possible price squeezing your margins to the point that you aren't making much on the job? You can still make it work with cannulated bar, but you are likely missing out on additional profits.

Let's take a look at some of the biggest issues.

Cannulated bar stock typically costs 10x that of solid bar.

Once you see how its made you can understand why it's so expensive.  The manufacturing process typically involves 7 or more steps starting from a raw inget -- forging, rolling, induction heating, extrusion, cold and hot drawing heat processing, and finishing.  Supplies are also limited as there is one main supplier for the world market leading to additional pricing pressure.

Leads times can be long.

Many customers report lead times of months.  Again with a limited base of suppliers for cannulated bar, you are at the supplier's mercy when it comes to delivery.  Will your customers be understanding when you tell them you had to delay their shipment?

Scrap is costing you more.

Your scrap costs are higher because you are paying for the added value of the hole over the entire length of bar, not just the amount you use to make the part.  If you can't find a good use for the left over scrap, recylcing will net you less because its lighter than solid bar.

So what's the soultion?

Gun drilling or twist drilling on your existing CNC machinery using Modulated Assisted Machining (MAM).  Drilling deep holes in difficult materials many times can be less effective than cannulated bar stock.  Adding MAM into the mix though provides a very controlled modulation of the tool in the Z axis allowing you to drill faster, get more life out of your tools, and have a more controlled process that fits into your existing equipment.  The science behind this ground breaking technology started at Purdue University, and after 5 years of development by M4 Sciences has been helping customers around the world with over 100 installations since 2010.

If you're tired of having to deal with the problems associated with cannulated bar stock, check out this new technology that just might make you more money while reducing your headaches.