Motion control boosts fence-post drilling throughput

On the manufacturing floor of British Columbia-based BKB Cedar Manufacturing, the whine of the drill motor and churning of its bit into tough cedar posts made a reassuringly steady cadence — until, too often, it didn’t.

Workers would manually position posts by moving a heavy carriage back and forth between drilling operations. They would then manually drill into the posts, expecting a smooth down-and-up motion, only to hit a knot that snared the bit and halted production. This labor-intensive process was already slower and more physically straining on operators than BKB Cedar wanted, but jams, dull bits, and other unexpected snags only made it worse. The company struggled to meet production deadlines — often adding a second operator to the drill station just to keep pace. But even with two people, production peaked at 600 posts per eight-hour shift.

“The initial thought was to add some sensors and maybe change the hydraulic valves to electric valves, then have it controlled by a PLC to accomplish pretty much the same thing,” said Glenn Zuhlke, owner-operator at MicroWest Design, the automation integrator BKB approached for help. “But when I went to have a look, I realized there could be a major speed advantage if we had better control of the hydraulic axis.”

Upgrading a system like BKB Cedar’s fence drill isn’t just about dropping in a new controller. The original fence drill was built in the 1980s and exemplified that era’s manual control systems. While the basic hydraulic concept remained sound, the manual carriage operation and mechanical stops reflected decades-old thinking about manufacturing efficiency. It was long past time for improvement.

MicroWest ultimately chose a hydraulic motion controller from Delta Motion known as the RMC to achieve major control improvements, but that was only part of the solution. As Robert de Rot of PQ Systems, who collaborated with MicroWest on the hydraulic design, explained, the broader process often involves a more comprehensive overhaul.

“It’s not just a matter of like throwing the RMC at the old valves and the old cylinders because that would not have worked very well at all,” said de Rot. “The existing system featured basic components, like a three-inch bore cylinder chosen to slow down an overly quick system due to rudimentary on-off valves. Their hydraulics needed a complete makeover … to get to the state of even having the opportunity to talk to an RMC.”

This involved careful assessment and multiple iterations. PQ Systems went back and forth a lot with the client to understand the motion, weights, and forces in play. Overhauling the system included sizing a new cylinder, selecting a correctly sized Moog D634 servo proportional valve, and integrating Temposonics position feedback. Through this detailed hydraulic and mechanical refinement, MicroWest and PQ Systems laid the foundation for advanced motion control. As de Rot put it, after the extensive work on the hydraulics, “the magic of the RMC took over from there.”

He added, “We went through several iterations of valves and hydraulic sizing to get the system right, but the Delta was the easy part.”

Zuhlke’s experience with other controllers led him to Delta Motion. MicroWest Design had used other controllers in the past, but each brought its own issues. Zuhlke recounts how one controller would lose its position whenever the power cut out. When MicroWest Design needed support for the bug, the manufacturer promised a fix in a later version, as if the customer could wait a year or more.

In contrast, after successfully implementing a Delta Motion system on a 13-axis project, Zuhlke knew he’d found his preferred solution.

“That project just went so well. There’s no way we’ll go back to what we used before.”

For BKB Cedar, Zuhlke, with guidance from PQ Systems on the motion controller selection, opted for Delta Motion’s RMC200. The controller provided three critical functions for the fence drill retrofit: vertical drill positioning, horizontal carriage movement, and pressure monitoring to prevent jams. The choice of the RMC200, specifically a seven-slot version, also provided BKB Cedar with room for future expansion.

“The solution uses the vertical position as well as the pressure to control the up-down movement of the drill,” explains Zuhlke. “The Delta controller subtracts the pressure readings from either side of the cylinder and converts that to force. If it’s going down too fast and there’s too much force, the controller sees that pressure feedback and slows the speed, so it doesn’t jam the drills.”

Before automation, BKB’s drill operators drove bits to mechanical stops, wasting motion and time. The Delta-powered system uses lasers to measure post thickness, enabling an exact 1.5-inch drilling depth regardless of post variations. This precision enables smarter drilling profiles.

“With Delta’s motion control,” said Zuhlke, “we go full speed down until we get to the wood, then we slow the drilling speed. And when it comes out of the hole, we go full speed, as well. We promised the client fifteen-second cycle times. They’re averaging ten now.”

The ease of use of the Delta Motion platform was a significant factor in the project’s success. Once PQ Systems helped define the hydraulic requirements, the application was handed off to Glenn Zuhlke at MicroWest. His familiarity with Delta controllers ensured a smooth transition. Robert de Rot highlighted this, noting that Glenn “didn’t need to call for assistance with the Delta, nor did he call Delta support — not once” for the Delta-specific aspects of the project.

Despite a very smooth design and implementation process for the Delta controller, the BKB Cedar job had one or two issues to iron out related to the overall system. Notably, MicroWest Design encountered an unexpected vibration. Delta helped them discover that the problem was actually mechanical in nature and not related to the drilling motion. However, along the way, Delta exposed MicroWest to something they’d never tried before: using Delta’s bundled RMCTools software to tune motion using a previously captured plot of motion.

This capability helped optimize performance and let MicroWest and BKB continue fine-tuning the system while running. Operators would put the axis through the motions during normal operations as they produced the product. These recorded motion plots were then used to tune the axis on the fly.

Zuhlke emphasizes Delta Motion’s support advantage. “Go to Delta quickly for help. If you’re thinking about implementing a project, call somebody at Delta and tell them what you’re planning. They’ll help you come up with the best solution right away.”

Results were dramatic. The revamped drill system shattered BKB’s production records while dramatically reducing physical strain on operators. “Their previous record was between five and six hundred posts [per shift] with two people,” Zuhlke noted. “Now they’ve topped over eight hundred with one operator. They’ve almost doubled their previous rate.”

Beyond throughput, the system eliminated the frustrating downtime caused by jammed drills and the safety hazards of manual jam removal.

Previously, operators would encounter knots at typical rotation speeds, and the bit would jam before the operator could detect a problem. Once a bit jammed, getting it out was difficult.

“Whenever something happens out of the norm, that’s when there’s a possibility of injury,” added Zuhlke. When you need to unstick or fix something, what’s your first instinct? Reach in, right? You shouldn’t get your hands in there, but the temptation is always to try and get production running again.”

Fortunately, the Delta-based solution monitors both pressure and motor current. The system automatically recognizes changes at the microsecond scale and slows the bit accordingly to eliminate jams and their resulting downtime, improving both throughput and safety. The automated system also eliminated the need for operators to lean in close to manually align posts, replacing human positioning with laser guidance that keeps workers at a safe distance from the drilling operation.

This vigilance also improves quality. “Now we’re drilling a one-and-a-half-inch hole,” said Zuhlke. “We’re not just ramming the drill down to a stop that’s strangely high off the work surface. The system actually sees the top of the post and knows precisely how far down we need to go. So, the output is exactly to spec, and customers are happier with the quality.”

So, what of the impact on BKB’s workers? These days, there’s uncertainty about how automation can and will impact human workers. Obviously, BKB’s upgraded drill system is only partially automated, but this Delta upgrade and others brought Zuhlke to an unforeseen insight into the effect of automation — or at least this sort of partial automation — on worker productivity.

“Automate for as much performance as you can,” he advised. “If there’s an operator there, you want to keep him busy. The machine should push the operator.”

With BKB Cedar’s new system, the post platform automatically produces the finished product once drilling is complete. There’s less pause between drill cycles, so it gives operators an incentive to work faster. This approach contrasts with Zuhlke’s previous experiences. “I’ve automated things in the past that would bore the operator, that would slow things down because performance wasn’t prioritized. You want to push the operator, not bore them. Help them rise to the challenge, like how your tennis game improves when you’re up against a slightly better opponent.”

Delta Motion | deltamotion.com