Today honing is straightforward to introduce in-cycle or in-process and the latest machines make it affordable, cost effective, operationally efficient and risk reducing.  Beyond just precision finishing, honing is also a good way to remove material, to replace internal grinding and to create tight geometry and an exact surface finish (holding tolerances down to a micron, with sub-micron adjustment), all to a consistent standard. This close tolerance finishing can also mean that reaming and hand polishing operations can be eliminated altogether. Indeed, new applications for honing appear every day.

Whilst the latest energy-efficient machines keep all of the precision and improved repeatability, they are much faster than the manual process and allow unskilled operatives to fill a gap left by the retiring masters, aided by computer control and programmable process. They also avoid the significant capital expense and opportunity cost of using CNC machines for this operation (to which some have resorted in order to fill the skills gap, but at overstated cost).

The new breed of honing machines are set up by conversational programming via touch-screen, or uploaded programmes via USB.  This step of the process requires some engineering ability and is the one part of the approach that requires expertise.  Once programmed, the machine moves to exact input values, rather than being physically adjusted, so the variance introduced by the human factor is gone. Operation becomes a simple, clean, de-skilled and hands-free process, with workers protected by the improved safety features of sensor-controlled, failsafe, interlocking guards, which only allow operation once securely closed. Quick-release tooling makes for efficiency in operation, supporting an optimised process with reduced cycle time. This results in extended tool life and reduces the cost per part considerably.

In terms of volume, honing machines now exist for everything from prototyping and small batch production of 20 to 250 parts, through medium batch size or honing in process, right up to high volume production in excess of one million components. A huge number of parts are suitable for honing and some common examples include spools for hydraulic and servo valves, cylinder liners, bushes, gears, carbide dies and ceramic sleeves.

The scope for materials that can be honed with the new machines has also vastly expanded: Aluminium, brass, titanium and hard steel can be honed as standard, with harder materials such as ceramics, glass and inconel also within honing capability. These more ‘exotic’ materials may require job-specific abrasives and these can be developed to order.

For those needing an easy route into honing, it’s possible to use sub-contracting as an interim step to machine purchase, with support available – from feasibility on a part, to specification and new machine manufacture, to special tools and services, application development, process engineering, maintenance and training. This creates a risk-free way to bring honing in-house.

Honing now has a bright future for a whole host of reasons, such as the potential time savings, cost savings, efficiency savings and return on investment from using this process to transform a production line. As an example, consider the improvement in cycle time that took a batch of 300 parts from 25 hours manual honing down to just 45 minutes on the right machine with right tooling, fixtures and process – an exciting but not uncommon demonstration of the future in honing. And there's the potential for this process to grow considerably, way beyond what was ever possible as a manual engineering art.