Tips on How to Select an Automatic Labeling System


Exactly what is an automatic labeling system?

An automatic labeling system consists of three key components: a labeling head (or label applicator), a conveyor (or other product transport device), and an integrated control system each of which, in turn, have their own sub-components. Optionally, other operations can be added to the system, such as Hot Stamp coders, bar code printers (thus: print and apply), power unwinds (for extra large web capacity or feeding a barcode printer), verifiers (to make sure label is on and/or the code is readable), etc. When all of these components are fully integrated meaning they all work together without the need for human intervention, except for replenishing label stock, printer ribbons and physical changeover to a different product, and the system works through the entire speed range without need for readjustment of controls, you have an "automatic labeling system". (You should not assume that a manufacturer who claims to have an "automatic labeling system" really does! All to some degree have the basic components, but many, if not most, are independent components that are not fully integrated!)


Labeling Head (Label Applicator)labelhead.JPG (74574 bytes)

Web Unwind Reel

Pretty Simple - This is where you load your label roll (typically about 12" - 13" diameter. Larger rolls require a power unwind option.

Dancer Arm

Allows for smooth label starts, keeps web tension, and acts as a brake to stop the web unwind roll from overfeeding

Label Sensor

Detects the 1/8" gap between labels to alert the control system to initiate a label stop sequence. This is accomplished with an electro-mechanical switch (still standard on some brands), photoelectric sensor, or capacitive sensor (usually an option for clear labels).
Electro-mechanical switches are for the most part passe (outdated), except for small semi-automatic labelers.
Photoelectric sensors are common on most machines, but the sensitivity must be adjusted whenever changing label stock. However, CVC Self Set labelers automatically adjust this setting.

Peel Plate

The peel plate actually separates the label from the backing paper.  As the web breaks sharply over the peel plate, the label continues on in a straight line.

Drive Roller

The Drive roller is actually the workhorse of the labeling head.  In conjunction with a pinch roller, the drive roller pulls the web backing, starting and stopping with each labeling sequence. These are very similar on all machines. The difference in quality in labelers is not so much by the drive roller itself by the means by which the roller is driven and stopped. It is worth taking some time to go over the types of drive systems available and their advantages or disadvantages. This is very important information so please review this section carefully.

Clutch/Brake Systems

    Clutch/Brakes are the original method used to index each label forward. Basically a clutch brake functions by utilizing two electro-magnetic coils one of which energizes to engage the clutch (drive the label web) and the other engages the brake which stops the label feed. Clutch/Brakes were the original method for advancing labels, with the advantage that they were very inexpensive. Several companies still use them but it is impossible to have a truly "automatic labeling system" while employing a clutch/brake.  This is because of a timing factor that is inherent in the actuation of the clutch brake from one mode to the other. Furthermore, due to heat considerations of frequent cycling and inaccuracy of label presentation, speeds are limited to less than half of those possible when using a quality, fully integrated stepper or servo system.   We do not recommend a clutch brake system. You can buy our CVC Self Set labelers with the latest technology and high performance at about the same price as these low performing systems.

Stepper Motors

This is another confusing area for the purchaser of a labeling machine. There are A.C. (alternating current) and D.C. (direct current) stepping motors. D.C. stepping motors are further categorized as 2-phase and 5-phase.

A.C. Stepping Motors

A.C. Stepper motors are used on a few labeling systems, but not many. The advantage is they are relatively inexpensive. But the disadvantage is that they have a large step angle (about 12 degrees) creating inaccuracy and have limited speed capability. We do not recommend A.C. Stepping motors for anything but small desktop lableing systems! Besides, why pay the same money for 12 degrees accuracy when you can get a  CVC Self Set labeler with 0.36 degrees of accuracy?

D.C. Stepping Motors

What is a Stepping Motor?steppic.JPG (40705 bytes)

A stepping motor is an electromechanical device that converts electrical power to torque. But what makes a stepper motor different is that the shaft rotates in fixed angular units (steps) when its phases are energized in a predetermined order. 2-phase motors typically have 200 steps per revolution, whereas 5-phase motors typically have 500 steps per revolution.

 

 

 

stepconst.JPG (94316 bytes)

Stepper Motors are connected to a special driver which is actually a very high speed switching device that accepts input pulses from an encoder or PLC. For each input pulse it receives the motor advances one step. A 5-phase motor therefore requires 500 pulses to advance one full revolution.  However, to smooth out the operation of the motor and get greater accuracy, most drivers can be operated in what is called "half step mode". Half step mode allows the motor to advance with double the resolution or 1000 steps per revolution. So now the input pulses must also be doubled to 1000 pulses per revolution. Further divisions can be made by micro stepping.  However. micro stepping results in considerable loss of torque at each division and is not widely used in labeling applications.

step5ph.JPG (109630 bytes)

As you can see in the drawing above a 5-phase stepping motor has the advantage of resolution and accuracy over a 2-phase motor but the advantages do not end there. 5-phase stepper motors also have higher starting torque, run smoother and are quieter than 2-phase steppers.  The only disadvantage of a 5-phase stepper motor is that they are more expensive, but CVC Self Set labeling systems will not sacrifice quality despite our desire to build an affordable automatic labeling machine!

Servo Motors

Servo Motors are utilized only on labeling systems that require very high production speeds measured in hundreds of bottles per minute. Servo motors and control systems are very powerful, very accurate and very, very, expensive!  New! CVC now has the CVC-302 Servo-Drive high speed labeler available. Under development for two years this is the top of the line machine for wrap applications. Click Here for Details!

 But our CVC Self Set automatic labeling systems have been engineered to meet the demand of at least 75% of the automatic labeler market, without need for modification!


Conveyor or "Product Transport"

For a product to accept a label some means must be provided to transport it through the labeling station. In the overwhelming majority of cases this will be a conveyor for transporting boxes, bottles, candles, or any of the myriad of products you can imagine. In very special circumstances where the product is unwieldy, or labeling must be done on a special production line due to some unique circumstance we can build a custom product transport or systems integration.

The most important feature that should concern you is not the type of conveyor you buy (although it must obviously be able to physically handle your product dimensions and loads) but how it is driven and its controls.

Gearmotors

There are several types of gearmotors, but we will concern ourselves only with the two types A.C. or D.C. that are most commonly used on labeling equipment.

A.C. Gearmotors

A.C. Gearmotors are utilized on very few labeling machines, but you should still be on the alert, as some are out there. AC motors are rugged, have a long life and are relatively inexpensive and plentiful. When used on labeling systems they are either of two variable speed types; vari-cone (belt drive via a a mechanically adjust variable pitch pulley) or through a special control driver that changes speeds electrically. The one major disadvantage of standard A.C. motor drives is a factor called "slippage" which basically means that as the load increases, a slight loss of motor r.p.m. occurs. In a labeling application this slippage can cause labeling inaccuracy, particularly if the labeling equipment uses timers (most do) to determine dispense timing. (We do not recommend labeling systems that use A.C. motors or timers!)

D.C. Gearmotors

D.C. Gearmotors are by far the most commonly used conveyor drive by labeler manufacturers, including CVC. But as you are well aware by now, significant differences exist in the quality of the motors and even more so in the controls that power the motor.  CVC uses only Bodine, the world leader for quality and durability in fractional horsepower D.C. Motors. (Need I say more?)

D.C. Controls

D.C. motors require a controller which converts alternating current into direct current. Typical of a D.C. controller is the adjustable speed pot which the operator turns to adjust the conveyor speed. In fact many machines are still built today that feature several speed pot knobs which the operator adjusts to coordinate the speeds of the conveyor, wrap belt, and drive roller (clutch/brake systems) by manual adjustment of the knobs. Most D.C. controllers used in this fashion are fairly accurate between 1% to 5% of speed regulation (depending on the quality), but must rely on a rather tedious and labor intesive set up procedure as well as timers or other means of regulating label application. Not recommended!.

D.C. Control Closed Loop

A Closed Loop D.C. control adds two components to the system above to replace the speedpot, a generator or encoder (pulse generator) mounted on the end of the motor or, in many cases, on the output shaft of the gearmotor and a microprocessor or PLC. Both systems monitor the input data (voltage or pulse), compare it to the PLC preset speed setting and then send a voltage back to the controller to adjust for any deviation from the desired speed. These systems can hold speed regulation to within +/- 1/2 r.p.m. or 0.06% at full motor speed.

Generator Systems

Small generators mounted on the motor shaft create a voltage that increases with motor r.p.m. The microprocessor compares this voltage input to the r.p.m. voltage preset and sends voltage back to the controller to adjust the motor speed to match. While this system does a very good job of maintaining accurate motor speeds it is not very useful in the overall scheme of an automatic labeling system since the information from the generator is not integratable. Not recommended!

Encoders

Encoders mounted on the motor shaft generate what is know as a "square wave" pulse (hence the term "pulse generator" is used rather interchangebly with "encoder"). These pulses are much more useful to a PLC because not only can this information be utilized to maintain the near perfect motor speed of the motor it is mounted to, but the "pulse train" that is generated can be utilized to control other motor speeds, input to counters which replace timers for more accurate labeling (more about this in the Integrated Control System discussion below), and if the pulse train rate is high enough even provide a base line for a stepper motor. But as in all our topics so far, not all pulse generators, or for that matter PLC's have the the resolution or counting speeds necessary for accurate labeling. For instance, some encoders deliver as few as 6 pulses per motor revolution while still others count deliver 360 pulses per motor revolution.

Example:

Assume a gearmotor running full speed has a motor speed of 1800 r.p.m. and an output speed of 30 r.p.m. with the motor turning a 6" pulley that drives a conveyor. The conveyor would travel 565 inches in that minute and 10,800 pulses would be delivered (using the 6 pulse per motor revolution model). Sounds impressive doesn't it? But a further look reveals that given +/- one pulse accuracy your label placement based on this one factor alone could vary a total of nearly 1/8 inch.
But there is a solution: High Frequency Response Encoders

High Frequency Response Encoders

High frequency response encoders are capable of delivering 360 pulses per motor revolution or, as in the example above, 648,000 pulses per minute, which translates to higher accuracy. Accuracy to the degree that total variability based on the terms as stated above would be less than 0.002" or two/thousandths of an inch!
The only problem here is that most PLC's are not even capable of counting at such high rates to take advantage of the accuracy that can be garnered by utilizing a High Frequency Response Encoder.

All
CVC automatic labeling systems include High Frequency Response Encoders with a high performance PLC that can take advantage of these very high pulse rates!


 

Fully Integrated Control Systemcvccontrol.JPG (80513 bytes)

       The heart of a labeling machine is its controls.   CVC supplies the latest in digital controls with it's exclusive Self Set system, which greatly simplifies initial setups automatically and allow storage of at least 50 setups into memory.  "Multiple Event Processing" permits higher labeling speeds than competing brands in this price range.   The exclusive "Self Set" feature automatically optimizes the controls for your bottle and label.  Complete changeovers can be accomplished in less than 2 minutes, without need for highly paid production line mechanics!

    All machine frame components are constructed of laser cut stainless steel and powder coated aluminum.  We will soon have a complete troubleshooting section on-line at this site, so that you can solve any problem at any time.

    And of course, you get Busch Machinery Customer Support with every purchase!  We service what we sell! Full one year warranty on all parts.

More on Controls

The control system of a labeler is supposed to make running your job easy, reliable, and accurate. The finest labeling system in the world featuring a highly accurate 5-phase stepping motor, automatic sensitivity adjusting label sensor, Bodine drive motors, closed loop D.C. controllers, and High Frequency Response encoders will not be able to deliver performance and ease of use without a well designed control system that is fully integrated with all the components.

Most labeling machinery is not fully integrated which means that labeling accuracy is lost, setting up a job may require highly skilled (i.e. highly paid) personel, and valuable production time is lost.

Non Integrated Control System

Set up Procedures for labeling with a typical Non Integrated Control System for Wrap Around Labeling, even if you have run this job before:

  1. Place label roll on Web Unwind Table and thread through machine.
  2. Adjust guide rails and pressure pad for bottle size.
  3. Set Conveyor Speed
  4. Set Wrap Belt Speed - rough setting (slightly faster than conveyor speed)
  5. Set and match Drive Roller speed to Wrap Belt Speed
  6. Adjust Label Sensor sensitivity
  7. Set Label Stop delay timer and/or physically reposition the sensor
  8. Set Product delay timer and/or physically reposition the Product Sensor
  9. Observe labeling and adjust Wrap belt to more precisely match Drive Roller speed.
  10. Readjust as required (fairly often)
  11. Discover labeling speed is either to fast for an unstable product or too slow for production.
  12. Repeat Steps 3-11 as many times as necessary until the controls are set just right.
  13. Waste a lot of labels!

And Wrap Around Labelers are the easiest type to set up! Try setting up a front and back labeler with this type of controls.

Fully Integrated Control System

Same Wrap Around setup as above:

  1. Place label roll on Web Unwind Table and thread through machine.
  2. Adjust guide rails and pressure pad for bottle size.
  3. Press "CALL" and "3" and "ENTER" on the touch pad! Done!

Perfect Recall of all motor speeds, label positioning, sensitivity settings, product spacing, etc. And if you want go faster or slower simply press "+" or "-" on the touch pad and keep running, because, since no timers are involved, your settings will remain perfect! CVC Self Set labeling systems are fully integrated! Save up to 50 setups into memory. But there is more!

The first time you run a bottle and  label Self Set features an automatic setup routine which optimizes all critical settings including conveyor speed, wrap belt speed, drive roller speed, label stop position, and label feed "timing" (actually counters, more in a moment).

Here's what you do to run as above:

  1. Place label roll on Web Unwind Table and thread through machine, removing a label from in front of the label sensor..
  2. Adjust guide rails and pressure pad for bottle size.
  3. Press "F1" on the welcome menu and place a bottle on the conveyor. Done!

The Self Set routine will run a routine that counts the number of pulses for the bottle diameter as it passes the product sensor, it then takes a sensitivity reading of the backing paper where you removed a label, starts the stepper, starts counting the number of steps from the leading edge of the first label it senses, determines the gap width between labels, reconfirms on a second label, does all of the math to calculate label stop position, and perfect bottle label dispense timing and then goes into run mode. From there you can make any changes in speed without affecting label application quality and then save it to memory for an even faster setup next time! It has never been easier!

These fully integrated controls sound great, but aren't they expensive?

Yes, fully integrated controls are expensive, if built two or three units at a time, as most manufacturers do. But CVC Self Set automatic labeling systems are mass produced to lower the per unit cost. That's why CVC includes a full standard package that includes all of the above plus, product count, decrementing label count with low label warnings, auto shutoff if labels run out, hot stamp print signal outlet, and RS-232 communications port for adding other peripherals or interfacing with other computers. It is actually easier to package everything into our controls (and not have to make changes) than to "custom feature" you to death. 


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