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Positioning Equipment At Each Level Of Welding Automation
PrestonEastin Posted 02/19/2020
However, the decision to automate is serious and depends on your application. As such, clearly understanding what each level of welding automation offers will enable you to select one that suits your application. You can even customize a solution to your part geometry or footprint, so you can purchase equipment tailored to your welding process.
The levels of welding automation
Because welding automation is a vague term that is difficult to quantify, it is critical to understand what the levels of automation are, as each provides a unique value add to a process. Of course, budget is a key driver for determining which level of automation will be integrated into your system, which is why partnering with a product expert who can customize a positioner is critical.
The baseline: Manual equipment
Many traditional processes use manual equipment that relies on experienced operators. Manual equipment is ideal for small batch runs or lighter parts, such as smaller vessels and tanks. Some systems have manual components, such as a hand crank tilt on a 2-axis positioner that allows operators to tilt welding pieces in place before the positioner begins powered rotation. However, when fabrication shops are pressured to make repeatable parts at higher quantities, they need a consistent process that is only enabled by adding a level of automation.
The levels of automation, from the lowest to the highest level, are:
- Powered equipment
- Fully integrated positioner control panels
- Programmable Logic Controllers (PLCs) with Human Machine Interface (HMI) screens
- Welding positioners integrated with robots
1. Powered equipment
The transition from manual equipment to powered equipment is triggered by increased throughput demand, part geometry, and/or increased weights, which can result in operator safety issues. Switching from manual to powered equipment involves integrating a welding positioner into your system. Positioners at the first level of automation use a direct drive connected to a potentiometer that allows operators to control speeds. A positioner can increase output and lower manufacturing costs while enabling controlled part rotation and positioning.
For example, a customized welding turntable is ideal for rotating larger workpieces with weights from 100 pounds up to 200 tons at a controlled speed around a vertical axis. Essentially, positioners facilitate a consistent process for making repeatable parts at higher quantities. Many times, positioners are integrated with systems that have robots (see below) to further increase accuracy and efficiency.
2. Fully integrated positioner control panels
Adding an integrated control panel offers an added level of welding automation over powered equipment by integrating various pieces of equipment together into one panel. Positioners can move in an infinite number of axes, but control panels integrate them into one panel and allow for a consistent deposition rate, speed, tilt, rotation, and weld quality. In short, successfully integrating a control panel into a welding system allows operators to seamlessly control multiple axes of motion.
For example, a control panel can control both the fine adjustments of a welding manipulator performing two axes of motion, along with a welding turning roll performing an additional axis of motion by rotating a vessel.
It is also possible to integrate panel controls for supplemental equipment into your control panel. Selecting supplemental equipment is process driven, which is why there are a number of options available. The following are some popular ones:
- Weld cameras positioned on a welding manipulator to assure operators that the welding and tracking is correct.
- Tactile seam trackers to follow the weld joint and assist with multiple passes.
- Lasers to track and position the welding arc.
- Flux hoppers and flux recovery systems for sub-arc welding that dispense and recycle flux media.
- Cross slides for fine X & Y adjustments on a welding manipulator.
Because fully integrated positioner control panels are highly customized, it’s important to partner with an engineering staff that understands how to implement customized solutions.
3. PLCs with HMI screens
Before you jump to the highest level of automation — a robot cell with a positioner — consider if a PLC is more cost effective for your application. PLCs are the brains behind an automated welding process and signal welding equipment to perform repeatable positioning.
Although control panels can control several axes of motion, they have difficulty executing coordinated movement or repeatable positioning, because operators are challenged to control more than one axis of motion at a time. This is when a PLC with an HMI screen is ideal.
For example, let’s imagine you have an elevating headstock / tailstock that needs to move from the first position to another preprogrammed position, which is two meters down and rotated five degrees; a PLC can consistently move from one position to another in a repeatable manner. The logic and recipe for this action is based on customer recipes / specifications and will command the PLC to control multiple axes of motion as well as the positioners in a coordinated fashion.
The highest level of automation is an integrated weld cell with a robot and welding positioner or Robot Transport Unit (RTU) / Rail, which should be integrated if you need a consistent process, maximized repeatability and increased output. When selecting a robot and positioner for your welding process, consider the size, weight, and center of gravity offset of your part first, along with the constraints of your application (e.g., footprint availability).
All robots are controlled with a robot controller and can execute infinite positions within their reach. A robot can be programmed to control the way a part is loaded and unloaded as well as part rotation to minimize downtime and maximize welding efficiency and repeatability. Each axis can be programmed to move in a coordinated fashion for optimal part positioning. Although most robots inherently have only six axes of motion (a controller can usually accommodate additional axes), a side box can be added for additional axes as needed.
When seeking a robot for your welding process, we strongly recommend customizing it to your process, so you are only paying for what you need. For example, consider if you need a robot with a footprint of one meter but your RTU needs to be 2.4 meters — you should only have to purchase an RTU that is 2.4 meters, nothing more or less. If you’re restricted to purchasing a rail with 3 meters from standard lines, you may create an avoidable footprint issue.
Contact our team to learn how you can customize your automation solution and purchase equipment that precisely fits your specs.