Robots, lasers, torque, heights and calibrations — realizing an Internship could become a Career

Robots, lasers, calibrations

Image by MD. Obaiduzzaman Khan {link to}

To read Jeff’s first installment, go to:

The second leg of my internship programming industrial automation equipment at Precision Valve and Automation (PVA) brought me out of the reworks department and into programming custom production machines for a number of specialized customers.  My first project was programming two tabletop XYZ Cartesian coordinate Robots for HB fuller, a worldwide producer of industrial adhesive products, sealant products, paints and other specialty materials.  Their machine integrated a number of features that I had to familiarize myself with.  First was Laser Height Offset. This used a Micro Epsilon high precision laser to take height readings from their part.  Due to imperfections in the manufacturing process, the parts they fed into our machine had small height deviations.  The laser would read the height from the part and cross reference that with an optimal height value and calculate an offset for the Z-Axis allowing for better repeatability and overall final product.

Next is a needle height calibration with a digital dial indicator.  This would allow the customer to change the style of a dispense needle on the valve and have the machine automatically calibrate it.  This functions similarly to the laser height routines.  The machine will move above the dial indicator and lower the Z-Axis. Once the dial indicator reaches a set point, the Z-Axis will stop moving and record the position of the Z-Axis motor.  Based on the position of the motor, the Z-Axis will be offset so that the coordinate system of the machine will not change even though a different sized needle was installed.  These machines were also outfitted with high temp heat plates rated for 250 degrees Celsius.  My program had to constantly monitor the temperature of the heat plate to insure they were within operational and safety limits, and shut them down if anything were to go wrong.   These machines were run off by the customer and now reside in their facility.

Next was a machine for Rockwell Collins, who provide avionics and information technology systems and services to governmental agencies and aircraft manufacturers.  These machines were also XYZ Cartesian coordinate Robots but utilized two extra axes to drive a two part pumping system attached to the rear of the robot.   These pumping systems used two servo motors to drive plungers pushing material through 20oz cartridge into heated hoses which fed into a dispense valve.  After flowing through the dispense valve, the two materials would be mixed in a static mixing tube and finally be dispensed on the part.  These pumps had a number of features and sensors that needed to be monitored.  First was pressure.  The 20oz cartridges have been known to burst at pressures close to 200 psi.  So it was vital to shut down the machine if the pumps were getting close to that amount of load pressure. Next was the motor torque.  If for some reason the motor torque driving the pumps got too high, this could also burst the cartridge, so monitoring the command signal to the servo motors was also essential.  Next was low level, reverse and forward limit sensors. These sensors tell my program to stop running the motors before the end of their travel, preventing possible damage to the hardware.  Lastly was monitoring the temperature of the heated hoses connecting the pumping system to the workcell.   These are very expensive hoses and heating over the recommended temperature can permanently damage them.   The machine also uses a laser needle calibration block which uses three lasers to center the dispense needle and keep it calibrated.

This brings me to today, currently working on a production line for Continental Automotive.   These machines are designed to be tied into the customer’s facility network. The machine will use two barcode scanners to communicate with the customer’s product database and log data based on the systems performance.  I am currently testing the data transfer protocols specified in their MES (Manufacturing execution system).   Overall, this internship has furthered my skills and knowledge for programming and process design in automated industrial robotics. I will continue at PVA as a full time employee and hope to learn all there is to know about the industry; for a living, building robots is not a bad gig.

Jeffrey Leifer, CSMAT, Summer 2013 graduation


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s