Embedded PCs Keep Drilling Machines on Budget
The need to drill straight and precisely shaped holes has been with manufacturers since the very beginnings of industry. Ever since the introduction of hand guns and rifles, the precision benchmark has been set high for deep hole drilling. Even today, these drilling systems are often referred to as “gun drills” because gun and rifle manufacturing was one of the first applications to require ultra high drill precision.
Gun drill technology has moved into many other industries, such as the automotive, aerospace, and medical industries– basically any application that requires precision holes. Kays Engineering, located in Marshall, MO, is a major provider of high precision deep hole drilling systems and leads by providing the best new technology solutions for the modernized version of an age-old manufacturing challenge. With endusers located in North America and around the world, Kays Engineering must remain at the forefront of automation technology to meet the extremely high precision requirements and diverse drilling needs of its increasingly international customer base.
Kays Engineering has two well-established deep hole drilling systems in its Eldorado and DeHoff machine families. The main difference between the DeHoff and Eldorado lines is drill size. The Eldorado line is the smaller of the two with drill diameters up torequired by the customer.
When compared with competitive offerings, a major differentiator with the DeHoff machines is the use of flat ground ways rather than using linear guide ways. This provides peerless stability and helps minimize vibration in the drilling process, which could otherwise cause numerous quality problems in the finished product. DeHoff machines also offer a vast range of spindle speeds to provide maximum drilling flexibility.
The primary customer requirement for Kays Engineering is to be highly adaptable and flexible to every unique application. “While Kays offers a job shop-oriented and standardized machine with the Eldorado line, the DeHoff line of drills is often subject to requests for rather high levels of customization,” explained controls engineer Brandon Snell said. “Usually our customers have already finished the design and dimensions of their parts that are to be drilled. Kays Engineering must be totally flexible to adapt our machines to faultlessly drill these parts that have nearly limitless variance in shape and size.”
The DeHoff gun drill line has some standard elements such as the servos drives, motors and other standard motion components, but the machine is very application-specific.
In the past, Kays Engineering utilized a traditional PLC to control both a servo drive and variable frequency drive (VFD) via an analog interface. A grayscale, low-resolution display panel served as the operator interface.
In early 2006, Kays first started looking for new controls packages and considered six different vendor options. Snell sought a highly flexible controls platform that could efficiently accommodate a wide range of customizations and provide a hardware platform that could scale in processing power.
“Many motion control alternatives we evaluated were typically priced quite a bit more than the PC-based approaches. Simple economics was a major deciding factor in favor of PC-based control,” Snell said. “We encountered some controls from Beckhoff Automation during our search and thought that a DIN rail-mounted PC-based controller could be exactly what we were looking for. Once we decided to more closely evaluate Beckhoff and contacted them, we immediately received high quality support from their regional sales and application engineers to get our new system into development.”
Scalable, stable embedded PCs
In late 2006, Kays Engineering went full speed into programming and controls design toward Beckhoff PC-based control. Utilizing the scalable CX Family of embedded PCs, Kays Engineering selected the CX9010 Ethernet controller with Intel IXP420 CPU and XScale technology for the Eldorado series drills. The higher performance DeHoff machines now feature the CX1010 with a 500 MHz Pentium MMX-compatible processor. The CX controllers utilize EtherCAT — the high speed Industrial Ethernet system from Beckhoff. “Another major benefit to the embedded PCs is that they utilize Compact Flash for boot and memory instead of a hard drive,” Snell noted.
The previous grayscale, low resolution displays from another vendor were replaced with full color 6.5 in. Beckhoff CP7829 control panels with custom DeHoff and Eldorado logos integrated into the laminate front. The CP7829 also features numerous function keys and a numeric keypad, adding to the flexibility of the new display.
The panels connect to the CX embedded PCs via DVI/USB. The CP7829 is an IP65 rated display that does not require a control panel enclosure. It can be mounted directly to machines via a pedestal or swing arm mounting configuration with all peripheral cables concealed and routed through the mounting tubes. The CP7829 can help reduce cost and required space when compared to a standard IP20 rated touch screen.
The CX9010 and CX1010 run TwinCAT NC PTP software giving Kays Engineering integrated motion control functionality. “The ease of use and configuration of the CX embedded PCs and TwinCAT reduce our troubleshooting time. TwinCAT also has built-in motion control libraries, which saves a tremendous amount of programming time — we’re able to simply drop in the standard blocks of code we need,” Snell said.
“We also have the flexibility to create our own HMI using TwinCAT visualization software — this is all tightly integrated with the control software so there’s no worry about having the different software elements function perfectly together,” Snell added.
The ability to choose Structured Text “has greatly streamlined our programming,” Snell added. “While we can still use it, we are not restricted to Ladder logic and can program in all the languages established in IEC 61131-3. The fact that one line of code can handle an entire complex equation has really helped out. In the past there were occasions when I had to code averaging calculations in Ladder Logic: addition in one rung, then division in the next, and storing it in another rung isn’t as easy as just typing out the formula that I know.”
The system Kays Engineering created includes a “drilling parameters calculator” that allows end users to simply enter data on the material to be drilled, the required hole diameter, and the system automatically generates the appropriate feed rate and spindle speed for the materials to be drilled. Part program storage and saving files in the DeHoff and Eldorado machines has become extremely simple with the Windows-enabled embedded PCs as well, Snell said.
In addition to EtherCAT-enabled embedded PCs, Kays Engineering uses the Industrial Ethernet system as the motion fieldbus. Beckhoff AX2003 EtherCAT servo drives are paired with AM3042 servo motors to tackle the motion control of the Eldorado gun drill. The DeHoff line of gun drills use a wide variety of servo drive and motor combinations including, but not limited to the previously mentioned AX2003 setup as well as an AX2006 drive paired with AM3052 or AM3044 servo motors. The EtherCAT-based motion system provides speed and position control of the axis slide.
“One of the biggest factors that led to selecting EtherCAT was the almost ‘plug and play’ functionality it brings to our machine design,” Snell said. Previously, the servo drives and VFDs on the Eldorado and DeHoff machines required an analog 4– 20 mA loop and excessive cabling to communicate the machine load. That method was not as reliable as Kays Engineering wanted, especially considering the long cable runs that were required.
“EtherCAT constitutes a major improvement because it offers deterministic performance and provides much higher speed and reliability. Troubleshooting cabling that consists of basic Cat 5e Ethernet cables is also inherently simple and cost effective. It’s just one type of cable to manage rather than having to worry about six different types,” Snell said.
Beckhoff’s TwinCAT Modbus TCP library helps facilitate communication to the DeHoff and Eldorado VFDs. “With high performance EtherCAT equipped on all the Beckhoff devices and the ability to simply connect to other kinds of devices via Modbus using TwinCAT software, we’re able to reduce cabling efforts in even more places using standard, inexpensive Ethernet cables,” Snell noted.
“Overall, the new Eldorado and DeHoff control systems have become more economical than the previous systems. In addition to the higher performance, energy usage has been reduced by using more efficient Beckhoff servo drives. Today, there’s a more compact Beckhoff motor controlling the gun drill’s axis slide that can generate the same level of torque as the larger motor in our previous system.”
This improved flexibility and efficiency did not come at an increased cost for Kays Engineering. “We saw a dramatic controls cost optimization with the DeHoff machine — the Beckhoff control system with the CX1010 costs well more than 50% less than the previous traditional PLC-based system,” Snell said.
There were additional cost savings from the Beckhoff system on the improved entry level Eldorado machines using the CX9010. “This system permits slightly scaled down PC-based hardware, but utilizes the same TwinCAT NC PTP control environment. The Eldorado system with CX9010 costs more than 10% less than the lower performing system it replaced,” Snell said.
The savings Kays Engineering experienced did not stop at hardware cost. “Using EtherCAT and standard Ethernet cabling, we were able to cut two work days from the required wiring time of our Eldorado and DeHoff control cabinets,” Snell said.
End-user future focus
Customer reception for the new Eldorado and DeHoff machines has been equally positive and highly encouraging to Kays Engineering. “As a result of the strong feedback for these redesigned machines, at least 90% of the Eldorado and DeHoff machines will be equipped with Beckhoff PC-based control systems and EtherCAT going forward,” Snell said.
Kays Engineering has by no means reached the end of its PC-based control evolution. The CX1020 and CX1030 embedded PCs from Beckhoff provide even higher performance options and provide room to grow when Kays Engineering decides to add more axes of motion and further enhance the system features of their deep hole drilling systems. “We have the ability to simply scale up to the next controller in the CX Family. Most of the existing programming and controls design will remain the same for each new machine variant. We’ve optimized our machine design flexibility today and well into the future,” Snell concluded.