Is it a machine? Is it a robot? NCMT unveils Armroid machines from Okuma

When you think about it logically, building a machine tool with an integral robot as part of the construction from the ground up makes so much sense that you wonder why no-one has thought of it before.

The advantages are pretty clear: firstly, you don’t incur the additional expense of hiring a third party systems integrator (which can be considerable) because integration is built-in by default; secondly, the design saves on real estate because the robot is tucked away inside the machine’s working envelope; and last but by no means least, the machine tool and robot share a common, familiar CNC/operating panel interface.

Armroid (Arm Robot Intelligent Design) machines were inaugurally unveiled by Okuma at EMO 2019. As far as the UK was concerned, the official launch was earmarked for MACH 2020 – but then COVID-19 happened.

Now, NCMT is targeting a launch in February 2021. By then, surely, some clarity concerning COVID will be in place, and of course the vaccine rollout programme should be well underway. All being well, strictly controlled machine demonstrations will be up and running from the Coventry showroom early in the new year.

“We’re looking forward to showcasing this technology because, essentially, the concept of having a robot designed into the machine tool itself is an Okuma exclusive,” affirms NCMT’s divisional sales director Ian Horton.

“It’s all about control: if you bolt a third party robot onto a machine tool, you’re potentially introducing an additional layer of complexity in terms of ensuring the machine and robot communicate effectively with each other. You can program the machine – but then the robot still has to be ‘taught’ to perform a particular process.

“With Armroid machines, because the machine and robot are designed and built to operate seamlessly via Okuma’s OSP (Okuma Sampling Path) P300 CNC, the control always knows where the robot is relative to the machine,” he continues.

“You only have to program in the robot’s start and end point, and, as long as you’ve got the software’s collision avoidance system enabled and the process is modelled correctly, the robot will never collide with any objects in the machining envelope. To assist with the programming, there’s also manual pulse handle for precise positioning.

“Okuma’s OSP control with Roid Navi programming software makes everything really simple via pictorial views and walkthrough guides; all the clever stuff is going on behind the scenes – and you certainly don’t need to be an automation specialist to use it.

“It’s also intuitive – the software checks to see if a path is clear before proceeding so if you have to introduce a new tool into the process for example, that technically becomes an obstruction. But providing the new tool has been modelled in the software, it knows it’s there and automatically compensates, generating a new path.”

In the mix

So what kind of production environments are Armroid machines designed for? Richard Turner, general manager for Okuma products at NCMT takes up the story: “Because there’s a physical limit on the number of parts the workpiece stocker can accommodate, Armroid machines are perfect for companies that undertake high mix, low volume turning operations,” he explains.

“It’s all about saving time and maximising productivity. Instead of an operator standing at a machine loading and unloading parts, Armroid machines effectively free the person up to carry out other tasks; and if the set-up needs to be broken down to accommodate a one-off job for example, it’s just a simple case of moving the parts stocker aside and using the machine conventionally.”

And because we’re talking high mix, low volume, Armroid machines aren’t designed for lights-out scenarios where the same part is being manufactured in high batch quantities all night. Rather, this is all about gaining extra time for the operator to do something else – setting-up another machine for example. Minimising non-cutting time is the order of the day here.

Armroid technology is currently available on two Okuma machine models: the Multus B250II horizontal multi-tasking CNC mill/turn centre and the LB3000EX II Space Turn II lathe – which is currently set-up and raring to go in NCMT’s showroom.

The former features a 600mm maximum turning diameter, 750mm maximum turning length and 5,000rpm spindle speed. The robot’s maximum payload here is 10kg. The latter, Okuma’s flagship 2-axis lathe, is built on a high-quality box slant bed and proven thermal design. The maximum robot payload on this model is 5kg.

From a general perspective, Okuma’s reputation in the marketplace for producing highly precise, ultra reliable, extremely accurate machine tools is not in question here. Adding an integrated robot into the equation will only enhance the machines’ already impressive capabilities.

Well-stocked

One of the standout aspects of Armroid machines is that compared to a separate machine/robot loader configuration, they take up very little space. All you’ve got is the machine footprint itself and a slimline stocker. That’s it. And remember the machines can be used standalone if necessary without any automation. The best of both worlds.

The stockers themselves come in three variants: the first two – racks (two or four shelf) and carousel arrangement indexable pitch feed conveyors are designed primarily for shaft work; the third type – which features an elevating workpiece table – is for processing billets.

Whilst there are obvious physical limitations on the amount of raw material/finished parts the stockers can hold, there’s plenty of capacity for short production runs. The two shelf rack for example can accommodate six blanks and six finished parts up to a maximum diameter of 80mm; the four shelf rack can handle 10 blanks and six finished components up to 50mm diameter.

The pitch feed conveyor comprises 18 stations with capacity to handle parts up to 80mm diameter. The elevating workpiece table (billet) stocker has six stations and maximum diameter capacity of 150mm. In terms of workpiece lengths, it’s 440mm for both shaft-type stockers and 150mm for the billets.

Gripping stuff

Adding to the Armroid machines’ versatility is a choice of three robot arm end effectors which can be used in an automated environment (with the workpiece stocker) or simply as part of a standalone machining process to provide additional functionality.

The end effector configurations are undoubtedly a highlight of the whole Armroid concept. There are four to choose from: a parallel workpiece hand; a 3-jaw gripper workpiece hand; workpiece support rollers; and a mixed coolant/air blast nozzle. Up to three end effectors (but only one workpiece hand) can be on board at any one time.

“These end-effectors are incredibly versatile,” Mr Turner enthuses. “The parallel two finger gripper is ideal for shaft work applications and some billet work; the three-finger gripper is designed for billet work where you’re picking the material up from the end face rather than from the side.

“The support roller end-effector offers in-situ support for long shafts during machining,” he adds. “It’s a bit like a steady, except it doesn’t clamp the outside diameter. Instead it supports the shaft from underneath and is really effective at minimising chatter.

“The air/coolant blast nozzle does what it says on the tin. It’s main benefit is to break up stringy swarf that can wrap itself around a shaft diameter. This can be programmed so the nozzle follows a specific path – just behind a cutting tool for example – to prevent swarf build-up.

“It can also be used to initiate a thorough machine cleaning cycle to clear the working envelope of swarf and debris once a process is complete.”

Changing the end-effector is entirely automated, requiring no manual intervention – courtesy of an integrated storage/stocking unit located to the rear of the machine. The grippers are clearly designed with automation in mind, but the support rollers and air/coolant blast nozzle can be used very effectively in a non-automated, single part machining process.

Reap the benefits

Richard Turner has high hopes for Armroid machines in the UK: “NCMT and Okuma are well-established across a multitude of high-tech industry sectors such as aerospace, motorsport and medical and I think Armroid machines will do really well in these areas,” he observes.

“But I also believe they’ll appeal to smaller, precision subcontractors that specialise in high mix, low volume production. These companies often don’t know what’s coming through the door next so they – and their machines – have to be highly flexible and adaptable.

“We would urge companies looking to get into automation to take a look at Armroid machines. The benefits are clear: small footprint; guaranteed machine/robot compatibility; simple to use and operate and no hidden costs from additional resources like system integrators.”

NCMT www.ncmt.co.uk