Advancements in Single-Component Precision Dispense and Shot Metering Technology
Three new technologies have been developed that provide significant improvements for precision dispensing control of single-component materials in the CASE (coatings, adhesives, sealants and elastomers) market.* Each product provides a unique solution to a range of single-component dispensing challenges.
PGM Metering SystemThe PGM Metering System was developed for automated applications where precise metering and bead control are critical for production. It includes a control center and a precision dispense positive displacement gear pump that is driven by a high-torque servo gear motor. Available gear pump sizes are 6 and 20 cc per revolution.
The system provides precise metering control for single-component bead, ribbon or extrusion applications. Using gear metering technology, programmable servo motor controls and an optional integrated heat package, the PGM offers accuracies of ± 1%, along with the ability to quickly change speed. Flow rates, which range from 8-1,600 cc/min with high-viscosity materials (100,000 to 3 million cps), can be programmed using a touchscreen interface. The system can be used for dispensing materials at ambient temperatures and for hot-melt materials up to 350°F (176°C), with pressures to 2,500 psi (172 bar). The servo control of the dispense speed ensures that the system can match almost any automated bonding, sealing or gasketing application.
Metering accuracy is ± 1%. The modular system is configured with either Graco Supply Systems for ambient materials or the Therm-O-Flow® System for hot-melt materials.
PCF Metering SystemThe PCF Metering System provides a precise, continuous flow for sealant and adhesive dispensing. This closed-loop, continuous-flow metering and dispense system offers high accuracy with no shot reload times. With closed-loop, continuous-flow technology, material is constantly metered and controlled as it passes through the PCF fluid plate. This provides accurate control with no limitation on shot size. The primary components of the PCF are an advanced display module, fluid plate and field bus interface. With an accuracy capability of ± 1%, the PCF is ideal for a range of applications with lower material viscosities (1,000 to 1 million cps).
The advanced display module provides easy setup, monitoring and system diagnostics, as well as a USB interface for data download. The fluid plate incorporates advanced sensors that provide feedback to the system controls, which enables real-time adjustments to be made for changes in material temperatures, viscosities, dispense rates or robot speeds. The fluid plate also supports a flowmeter and fluid regulator.
The fluid control module located on the fluid plate receives a signal with requested flow rate information from the advanced display module. The module then checks the flow rate with the flowmeter and adjusts air pressure to the fluid regulator, as needed. The fluid control module constantly checks and adjusts while material is dispensed. This configuration ensures consistency and offers real-time response to deliver a precise, continuous dispense. In addition, the Gateway fieldbus module allows the PCF to communicate with other automated systems within the manufacturing process (e.g., DeviceNet, Ethernet/IP, Profibus and Profinet options).
SmartWare TechnologySmartWare™ offers a new meter and dispense method without a secondary metering system. The SmartWare Shot Dispense Kit allows end users to dose a preset amount of single-component material using a Graco pump. The kit comprises a local control module, sensors, cables and mounting hardware (see Figure 1). When the SmartWare Shot Dispense Kit is installed on a Graco Supply System, or Dura-Flo™ or Check-Mate® pump, it turns the pump into an accurate, cost-effective dosing system. (The Graco pump must be equipped with an NXT® air motor.) General industrial applications include cartridge filling, kitting, converting, cavity filling/potting and batch formulating/blending.
This new shot dispense system provides accurate dosing without flowmeters or gear meters in the fluid stream. Instead, a linear sensor tracks the pump position so the pump becomes the flowmeter. Using the primary pump as a metering system removes all secondary metering components from the fluid stream, which reduces cost and wear issues. This technology gives end users a low-cost solution when faced with urethane batching or dosing applications. It is an alternative to both manual methods (such as mechanical counters or scales) and fully automated batch systems.
The SmartWare system allows for shot sizes from 6 cc to 1,000 gal. Shot size accuracies range from 0.25 to 3%, depending on material, volume output, and system setup. The local control module offers a sequence mode, allowing the end user to dispense a series of up to 14 different shot sizes. The display shows the programmed shot size and the amount actually dispensed.
Other ConsiderationsThe PCF and SmartWare systems incorporate Graco Control Architecture™, the framework that provides end users with a quantum improvement in their ability to monitor and control fluid management processes. Graco Control Architecture reduces point-to-point wiring and unique circuit boards to cut back on cost and points of failure. In addition, it also incorporates shared modular components that can be easily upgraded. These features lead to improved process monitoring and control capabilities, shorter lead times, and improved product quality.
All three systems (PGM, PCF and SmartWare) are used in conjunction with hoses (ambient and/or heated) and Graco dispense valves, including the EnDure® auto dispense valve, the 1K Ultra-Lite™ precision dispense valve, and the Auto Plus™ valve.
SummaryPGM, PCF and SmartWare offer advancements in metering and flow control for ambient and heated single-component urethanes. PGM and PCF offer additional control for both robotic bead placement and volumetric dispense, while SmartWare offers control of volumetric shots and batch dispense. All three technologies represent significant advancements in the ability to meter and dispense single-component materials.
For more information, contact Graco at 8400 Port Jackson Ave. N.W., North Canton, OH 44720-0747; phone (800) 746-1334; fax (330) 966-3006; e-mail firstname.lastname@example.org; or visit www.graco.com/sae.
Editor’s note: This article is based on a paper given at the Center for the Polyurethanes Industry’s (CPI) Polyurethanes 2010 Technical Conference, September 2010.
*Developed by and available from Graco Inc.
SIDEBAR: Potential ApplicationsThe PGM and PCF metering systems must be used in conjunction with ambient or heated bulk unloader feed systems, which can be configured for either 5- or 55-gal containers. Typical urethane applications for PGM and PCF include:
- Solar panel rail bonding and frame sealing
- Window assembly
- Automotive applications including urethane windshield sealants, robotized window sealing, carpet bonding, headliner assembly bonding, bonding lead battery cells to polypropylene cases, head and tail lamp bonding, mirror bonding to casings, and dashboard insert bonding
- Bonding ABS plastic housings
- Speaker assembly bonding
- Filter end cap bonding and seam sealing