In these challenging economic times, plastics molders are
searching for new automation paths. This search is leading
to alternatives to buying new robots.
Refurbish Existing Robots
As a third option, injection molders can refurbish their existing robots, sometimes performing
retrofit work in-house. Many PLC and CNC-based robots can be retrofitted with off-the-shelf
controls, such as Logic One’s SIMPLE ‘PLC PLUS’ robot controls. Small to mid-sized molders
looking to save money by improving their current robots should consider these Compact Logix
and SLC-500 controls, with inherently easy software that requires minimal training for
troubleshooting & repair. These straightforward robot controls can be easily set-up and run
without complicated programming or ‘scripting’ by an automation engineer.
Various Options from Refurbish to Complete Remanufacture
There are a wide variety of gantry robots in the plastics industry. Designs range from simple
pneumatic actuators and induction motors driven by inverter (frequency drive) to fully articulated
servo motor systems. Although most electric motors use encoders for position feedback, some
inherently simple electric robots move an axis to end-stops for position control. These basic
robots require more set-up time and have less flexibility, but are very easy to repair. If a molder
runs the same part 24/7, he can save money with such low-tech systems.
Since both pneumatic and basic electric axis move to a limit switch, they provide what is called
point-to-point motion. Usually these basic controllers will move one axis at a time, and are also
referred to as sequential-motion or ‘rectilinear’ controls. Sometimes rectilinear robots will allow
two axis to move together via timers or position set-points, but such ‘blended motion’ systems
are limited to specific axis settings.
Another important point of interest involves speed and torque curves. Induction motors
(460Vac, 60Hz, 4-pole) with frequency drives normally run up to 1,800 rpm. One interesting
option with induction motors is ‘over-speed wiring’. By wiring a 1hp motor for 230V and running
it up to 460V at 120Hz, you can double the horsepower to 2hp while doubling the speed to 3,600
rpm and maintaining adequate torque. This ‘double-speed’ option provides low-end servo
speeds at a much lower cost, especially with single-drive sequential-motion robots.
Selecting pneumatic or hybrid, rectilinear or articulated motion, double-speed induction or servo
motors, depends on your application requirements, capital budget and payback needs. Don’t
make the mistake of thinking you can only afford pneumatics, or that you must buy expensive
servo robots. Each molding machine’s applications, job changeovers, mold tooling and pre/post-
mold operations will define what type of robot system provides the best return-on-investment.
Also, your level of technical expertise and manpower availability can help determine what type of
robots to purchase.
If you run the same job six days a week, or in-mold time is not important, a simple robot system
can best improve your ROI. If you need high uptime operation and don’t want to pay high
prices, a rectilinear robot with simple PLC controls can optimize your ROI. If you need high-
speed motion or have complex applications, an advanced servo robot will provide your best
payback.
Take notice that in buying new traverse pickers that are all pneumatic, cost savings quickly
dissipate as you learn the importance of speed control, jogging, teaching points and smooth
motion control. A hybrid robot that has one pneumatic axis, preferably the strip stroke, or a
hybrid that uses an induction motor with limit switches for the traverse axis is a better
alternative. But two or more pneumatic actuators will significantly reduce your financial
payback. A better alternative is to wait until you can afford all electric robots, buy a good used
or rebuilt robot, or consider leasing contracts.
The machine-tool industry has been rebuilding & remanufacturing machines for many years.
Recently, injection molders have realized the cost-savings to be found in rebuilding in-house
robots. Some plastics molders are even buying used robots at auction, and having them
retrofitted or rebuilt after purchase. So when is it advantageous to rebuild? When you have a
few or more of the same robot, and the robot’s mechanics are reliable and capable of faster
speeds. Obviously, robots that don’t have strong axis design are not good candidates for
rebuilding. Also, since most re-builders are within the U.S. & Canada, it is much easier to find
replacement parts for North American manufactured robots, which in turn makes rebuilding
feasible. Special care must be given to spare parts, technical support and programming with
foreign designed or assembled robots.
As established above, there are many different options when rebuilding robots, so you can
select your preferred level of new performance. Be aware that retrofitted robots and partially
rebuilt robots usually come with a limited warranty covering new parts and programs. Fully
rebuilt & remanufactured robots come with full warranties lasting 1-2 years. With all electro-
mechanical ‘wear & tear’ components replaced, such robots are LIKE NEW and may even offer
better performance that new robots, especially hybrid systems.
Robot Re-Deployment Summary
As an injection molder competing with off-shore manufacturers, you need to continuously
reduce production costs to insure profitability. One of the best ways of meeting this goal is to
automate parts handling at the mold machine. For small to medium sized molders that are
budget driven, buying used robots that have been refurbished is a good alternative to buying
new robots. Like ‘certified’ used cars, refurbished robots provide good cost savings at one third
of new pricing, while insuring adequate reliability & performance.
Re-building older pneumatic or electric robots, and converting them with servo motors increases
robot speed by 150-300%, reduces mold change-over time, improves machine up-time, and
increases positioning accuracy. All of these improvements allow injection molders to deliver
product faster while reducing costs. Such performance improvements can be obtained at 50%
of the cost of new robots, while extending robot lifetime by several to ten years. Unlike used
robots purchased at auction, a fully rebuilt robot comes with a 1-2 year full warranty, significantly
reducing your investment risks.
Plastics molders have several options besides popular pneumatic and high-end servo robots.
From Hybrid robots to INDRO and Double-Speed INDRO robots, frequency drives can provide
servo-like performance with somewhat lower speed & payload, but at much less cost. And
SIMPLE PLC-based rectilinear robots can perform many of the simple molding jobs without the
cost of multiple servo motors or non-standard proprietary controls.
Easy-to-use SIMPLE PLC-based robots allow small and mid-size molders a cost-effective way to
automate without the complexity of PC or embedded controls, and without the burden of
programming languages. And simple Do-It-Yourself PLC controls allow molders to perform
debug & service in-house, without waiting to pay high prices for call-in service engineers. If you’
re a molder looking to improve automation on a set budget, consider the cost savings and
reliability of rebuilt and refurbished robots. Money saved redeploying existing robots can be
used for other important projects, or to improve your profitability.
searching for new automation paths. This search is leading
to alternatives to buying new robots.
Refurbish Existing Robots
As a third option, injection molders can refurbish their existing robots, sometimes performing
retrofit work in-house. Many PLC and CNC-based robots can be retrofitted with off-the-shelf
controls, such as Logic One’s SIMPLE ‘PLC PLUS’ robot controls. Small to mid-sized molders
looking to save money by improving their current robots should consider these Compact Logix
and SLC-500 controls, with inherently easy software that requires minimal training for
troubleshooting & repair. These straightforward robot controls can be easily set-up and run
without complicated programming or ‘scripting’ by an automation engineer.
Various Options from Refurbish to Complete Remanufacture
There are a wide variety of gantry robots in the plastics industry. Designs range from simple
pneumatic actuators and induction motors driven by inverter (frequency drive) to fully articulated
servo motor systems. Although most electric motors use encoders for position feedback, some
inherently simple electric robots move an axis to end-stops for position control. These basic
robots require more set-up time and have less flexibility, but are very easy to repair. If a molder
runs the same part 24/7, he can save money with such low-tech systems.
Since both pneumatic and basic electric axis move to a limit switch, they provide what is called
point-to-point motion. Usually these basic controllers will move one axis at a time, and are also
referred to as sequential-motion or ‘rectilinear’ controls. Sometimes rectilinear robots will allow
two axis to move together via timers or position set-points, but such ‘blended motion’ systems
are limited to specific axis settings.
Another important point of interest involves speed and torque curves. Induction motors
(460Vac, 60Hz, 4-pole) with frequency drives normally run up to 1,800 rpm. One interesting
option with induction motors is ‘over-speed wiring’. By wiring a 1hp motor for 230V and running
it up to 460V at 120Hz, you can double the horsepower to 2hp while doubling the speed to 3,600
rpm and maintaining adequate torque. This ‘double-speed’ option provides low-end servo
speeds at a much lower cost, especially with single-drive sequential-motion robots.
Selecting pneumatic or hybrid, rectilinear or articulated motion, double-speed induction or servo
motors, depends on your application requirements, capital budget and payback needs. Don’t
make the mistake of thinking you can only afford pneumatics, or that you must buy expensive
servo robots. Each molding machine’s applications, job changeovers, mold tooling and pre/post-
mold operations will define what type of robot system provides the best return-on-investment.
Also, your level of technical expertise and manpower availability can help determine what type of
robots to purchase.
If you run the same job six days a week, or in-mold time is not important, a simple robot system
can best improve your ROI. If you need high uptime operation and don’t want to pay high
prices, a rectilinear robot with simple PLC controls can optimize your ROI. If you need high-
speed motion or have complex applications, an advanced servo robot will provide your best
payback.
Take notice that in buying new traverse pickers that are all pneumatic, cost savings quickly
dissipate as you learn the importance of speed control, jogging, teaching points and smooth
motion control. A hybrid robot that has one pneumatic axis, preferably the strip stroke, or a
hybrid that uses an induction motor with limit switches for the traverse axis is a better
alternative. But two or more pneumatic actuators will significantly reduce your financial
payback. A better alternative is to wait until you can afford all electric robots, buy a good used
or rebuilt robot, or consider leasing contracts.
The machine-tool industry has been rebuilding & remanufacturing machines for many years.
Recently, injection molders have realized the cost-savings to be found in rebuilding in-house
robots. Some plastics molders are even buying used robots at auction, and having them
retrofitted or rebuilt after purchase. So when is it advantageous to rebuild? When you have a
few or more of the same robot, and the robot’s mechanics are reliable and capable of faster
speeds. Obviously, robots that don’t have strong axis design are not good candidates for
rebuilding. Also, since most re-builders are within the U.S. & Canada, it is much easier to find
replacement parts for North American manufactured robots, which in turn makes rebuilding
feasible. Special care must be given to spare parts, technical support and programming with
foreign designed or assembled robots.
As established above, there are many different options when rebuilding robots, so you can
select your preferred level of new performance. Be aware that retrofitted robots and partially
rebuilt robots usually come with a limited warranty covering new parts and programs. Fully
rebuilt & remanufactured robots come with full warranties lasting 1-2 years. With all electro-
mechanical ‘wear & tear’ components replaced, such robots are LIKE NEW and may even offer
better performance that new robots, especially hybrid systems.
Robot Re-Deployment Summary
As an injection molder competing with off-shore manufacturers, you need to continuously
reduce production costs to insure profitability. One of the best ways of meeting this goal is to
automate parts handling at the mold machine. For small to medium sized molders that are
budget driven, buying used robots that have been refurbished is a good alternative to buying
new robots. Like ‘certified’ used cars, refurbished robots provide good cost savings at one third
of new pricing, while insuring adequate reliability & performance.
Re-building older pneumatic or electric robots, and converting them with servo motors increases
robot speed by 150-300%, reduces mold change-over time, improves machine up-time, and
increases positioning accuracy. All of these improvements allow injection molders to deliver
product faster while reducing costs. Such performance improvements can be obtained at 50%
of the cost of new robots, while extending robot lifetime by several to ten years. Unlike used
robots purchased at auction, a fully rebuilt robot comes with a 1-2 year full warranty, significantly
reducing your investment risks.
Plastics molders have several options besides popular pneumatic and high-end servo robots.
From Hybrid robots to INDRO and Double-Speed INDRO robots, frequency drives can provide
servo-like performance with somewhat lower speed & payload, but at much less cost. And
SIMPLE PLC-based rectilinear robots can perform many of the simple molding jobs without the
cost of multiple servo motors or non-standard proprietary controls.
Easy-to-use SIMPLE PLC-based robots allow small and mid-size molders a cost-effective way to
automate without the complexity of PC or embedded controls, and without the burden of
programming languages. And simple Do-It-Yourself PLC controls allow molders to perform
debug & service in-house, without waiting to pay high prices for call-in service engineers. If you’
re a molder looking to improve automation on a set budget, consider the cost savings and
reliability of rebuilt and refurbished robots. Money saved redeploying existing robots can be
used for other important projects, or to improve your profitability.
| RE-DEPLOYING ROBOTS FOR PLASTICS INJECTION MOLDERS |
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