Every machinist learned their craft on a horizontal lathe and if you walk into any tool room or machine shop in the world, the odds are good that you’ll find at least one lathe in use. Of course, turning doesn’t have to be done horizontally. Vertical lathes flip turning on its end, spinning parts like a top rather than a car tire. Inverted vertical lathes go one step further and turn vertical turning on its head.
What is Inverted Vertical Turning?
In a vertical lathe, the chuck is located on the bottom of the machine so that parts clamped into it are pointed up. The principle benefit of this arrangement is that gravity works to your advantage for workholding, helping to seat the part.
However, with an inverted vertical lathe, the chuck is located at the top of the machine so that parts are clamped pointing down.. Using this type of lathe also means that you’re moving the part toward the tool, rather than vice versa.
Advantages of Inverted Vertical Turning
So, why use an inverted vertical lathe?If you consider a part which is on a sub-spindle below the turning tool, you’re basically in a situation where you are turning your chips into the tool path or the interior of the part. Those chips you’re trying to remove can have a detrimental impact on the quality of the part. If the workpiece is located above the tool instead, gravity is working to your benefit to allow all the chips to escape the part without any detrimental effects on the quality of the workpiece.”
This means that just as with a conventional vertical lathe, gravity works to your benefit on an inverted vertical lathe. The difference is that rather than helping with workholding, gravity helps with chip removal.
Applications for Inverted Vertical Turning
As with any turning operation, the applications for inverted vertical turning all involve round parts. For example, “any gear that you’d put in an automatic transmission,”
Differential ring gears, pinion gears, planetary carriers, hubs, flanges and yokes of various sizes can all be produced using an inverted vertical lathe.
For high volume applications typical in the automotive, appliance and consumer goods industries, inverted vertical turning is ideal where pick-and-place robotics caps line speed, or where the configuration of transfer lines makes it difficult to integrate a conventional turning center.
Many press-fit or shaft assembly operations, for example, are performed in vertical setups, reducing the need to reorient parts for downstream processes as they come off the vertical center. Similarly, the carousel’s built in “buffer” can replace accumulator systems between the turning center and downstream processes, reducing line stoppages when out-of-tolerance parts are detected and removed. And with gravity allowing minimal swarf and coolant residue on the parts, cleaning prior to downstream operations can be simplified or eliminated entirely.
Is Inverted Vertical Turning Right for You?
If you’re working with round parts, then you’ll more than likely need turning. When it comes to inverted vertical turning, volume is the key.
“Any round part that needs to be turned and which has some volume behind it is going to benefit from our machines’ self-loading,”before adding the caveat that, “This is not a machine that would do well in the environment of a job shop. Job shops require a lot of input from the operator on a case-by-case basis. But for any round part that has any volume, if you’re setting up for a thousand-part run, you can be assured that the machine will be very efficient in the process.”
Inverted vertical turning may flip the process on its head, but it’s still a machine tool, and standard machine tool practice still holds true, from toolpath coding to speeds and feeds.
For manufacturers contemplating machining cells using general purpose robotics tending two or more horizontal centers to feed a hungry line, inverted vertical turning offers lower overall cost in a smaller footprint with high throughput.
Vertical turning has been around for over a century, but if it was invented today, engineers would identify it as made for automated part production. Inverting the process lets smart manufacturers take full advantage of gravity; it’s like a free actuator or additional axis, without the cost or complexity.