Photographer: Monty Rakusen | Copyright: Copyright terms apply
Creating large-diameter holes in hard materials poses significant challenges for engineering companies, from excessive material loss to high tool wear and energy consumption.
Trepanning, which offers a practical and cost-effective solution, uses a more targeted cutting method that reduces waste and improves overall efficiency. But what is trepanning, and how does a trepanning tool work?
What Does Trepanning Mean?
In machining, trepanning refers to a hole-making process that removes a circular section of material - known as a core – in one piece, rather than drilling and converting the entire volume into chips. While the term originates from an ancient surgical technique used to bore holes in the skull, trepanning in modern manufacturing is about efficiency and material preservation.
Trepanning is conducted using a specialist cutting tool which is designed to cut annular grooves in solid workpieces. Instead of fully removing the interior material like a conventional drill, the trepanning tool creates a ring-shaped cut, leaving the centre core intact. This significantly reduces material waste, especially in large-diameter operations.
How Trepanning Differs From Standard Drilling
The key difference between trepanning and traditional drilling lies in how the material is removed. Standard drills convert the entire volume of the hole into swarf: as well as consuming more energy, this also generates unnecessary waste, which is especially problematic when working with expensive alloys.
On the other hand, trepanning leaves behind a solid core that can be repurposed or recycled. Also, because the cutting area is smaller, less mechanical force is required, thereby placing less stress on both the tooling and the machine. For large holes, in particular, this results in smoother cuts, longer tool life, and fewer thermal distortions.
What Is Trepanning Used For?
Trepanning is ideal for applications that require large holes in hard metals or thick-walled components, for example in aerospace, oil and gas, and heavy manufacturing. The process is particularly valuable when working with stainless steel, Inconel, or titanium, where material cost and tool wear are significant concerns.
Engineers frequently use trepanning to prepare billets for further machining, create hollow cylindrical parts, or extract test samples. It’s also used in scenarios in which a through-hole isn't required, and blind cuts are acceptable.
A less common use is to remove large amounts of material from the outside diameter by trepanning and then cutting the outer ring away from the remaining core. This is a cost effective way of removing very large amounts of material from a bar with a large flange at one end and a smaller diameter for the balance of the shaft.
Why Trepanning Is More Efficient
Apart from material savings, trepanning offers some important advantages.
By removing large volumes of material more quickly, trepanning reduces cycle times, minimises tool wear, and decreases power consumption. The retained core can often be reused for internal tooling or gauging purposes, increasing operational value and if not used, increase the recycle sale price. For high-volume or specialist jobs involving large bores, a trepanning tool can significantly reduce costs.
Get A Free Quotation From Hone-All Today
At Hone-All, our sub-contract trepanning service is a cost-efficient alternative to deep hole boring for creating large diameter holes in shorter billets, and is ideal for customers who don’t have the equipment or skilled staff to carry out trepanning in-house.
