BLANKING LINE ENHANCES PRODUCTIVITY FLOW FOR
MAJOR SINK MANUFACTURER
Blanking lines are used to produce tight tolerance blanks for manually fed or robotic fed downstream operations. These downstream operations may include stamping, rollforming, punching and notching, wing bending or a combination of these operations. The blanking line is the heart of the manufacturing operation. If the blanking line goes down, an entire plant could be shut down in a few days depending on inventory levels and operating procedures. Oftentimes, manufacturers are then forced to outsource blanks at higher costs from a local service center, adversely affecting production schedules and profitability.
Job versatility and flexibility
Ideally, a blanking line should be designed and manufactured to handle multiple presses requiring different blank sizes. The versatility of the blanking line allows for quick changeover from coil to coil. This line, designed to produce accurate blanks for a major sink manufacturer, is rated for material from .020 to .075" with a width range from 10" to 48" length for handling coil weights up to 15,000 lbs. A longer stacker would be required to run blanks as long as 96" in length, but the rest of the equipment would remain the same.
Designed for surface critical applications
This line is designed to process surface critical Stainless Steel while incorporating technology to speed and simplify coil loading and centering. Blanks containing scratches and marks would have to be rejected by the manufacturer. With this in mind, let's walk through the line. The coils come to the line with the "eye to the sky" and are placed on an upender by either a fork truck or overhead crane. The coil is then upended so that the eye of the coil is now horizontal and aligned with the mandrel. The coil car then picks up the coil from the upender and indexes the coil onto the uncoiler mandrel. Coil cars are especially useful in situations where space limitations do not permit the use of turnstiles or double reels. All surfaces that come into contact with the coil are covered with a high-density micarta for protection. Once on the uncoiler the mandrel is hydraulically expanded and rotated into position. Hydraulic expansion of the mandrel was recommended for this line to accommodate the frequent loading and/or unloading of coils. This allows for push-button expansion of the mandrel versus the labor-intensive manual process. The hold-down roll is lowered, strapping is cut from the coil and the peeler blade is extended to peel the leading edge of the coil. The coil is advanced forward in the jog mode onto the peeler table. When running surface critical material paper is usually interleaved between raps by the metal supplier. A paper rewind unit is utilized for rewinding interleaved paper as the material is paid off the coil.
Ease of thread up
Chances are, when cursing is heard on a coil feeding line,
operators are involved with the frustrating process of threading
up the material. This line utilizes a hold-down peeler system
to facilitate easier, faster thread up. Once the material
is on the threading table, the table is raised to back bend
the material on the breaker bar giving it a snowplow effect
to facilitate the threading process. While not included in
this line, a cropping shear could be located at this position
to remove both head and tails of coils or to take samples
throughout the coil for metallurgic testing. The material
is then fed into the entry pinch roll and into the straightener
where the coil set is removed from the material. The straightener
is equipped with: 100FPM modulating drive, ultrasonic non-contact
loop control, cluster gearing, seven (7) smooth chrome finished
straightening rolls at 2.8" diameter and 3.25" center distances,
four (4) chrome finished pinch rolls at 4.2" diameter, digital
roll position readout, automatic central lubrication, air
lifted entry and exit pinch rolls, full radius lifting exit
cascade with polyurethane rolls, angular head mounting, handwheel
adjusted self-centering edge guides.
Removing coil set
The objective in the straightening process is to provide material that is of adequate flatness for smooth feeding to downstream equipment. While this line features a seven- (7) roll straightener, additional straightening rolls or a leveler will provide increased capability of removing coil set. The straightener rolls can be increased to eleven (11) or even seventeen (17) in some cases.
When the incoming material has shape defects that will effect the downstream operations a leveler would then either replace the straightener or come after it and only be used on certain products. The leveler has the capability to remove shape defects such as edge wave, center buckle and quarter buckle. The leveler also has the capability of inducing all of the above shape defects in to prime material. In some roll forming applications edge wave is actually induced into the strip to help produce a better part. For the most part, if stamping, bending or forming will occur; a straightener is all that is required.
Advanced control technology
The settings for the straightener are powered and controlled from a touch screen. High rise straightener head design, which lifts the upper bank of straightening rolls by means of a jack screw system, provides excellent roll cleaning accessibility The touch screen is an intricate part of this system and there are actually two on this blanking line -- at the straightener and at the four-roll feed. They comprise what is called Total System Control (TSC). The interface provides complete operator prompting of threading procedures, maintenance schedule and service points for the entire system, as well as in-depth diagnostic fault messages with recommended remedies.
The ServoMax TSC system incorporates a coil loading station, uncoiler, high performance 7,11 or 17-roll straightener and an independent precision ServoMax 4-roll servo feed. The precision ServoMax TSC servo feed system is capable of accurately feeding +/- .005". Coil weights from 10,000lbs. - 80,000lbs. and widths from 24" to 84" can be processed by CWP's ServoMax TSC systems. This system nearly eliminates the need for a separate PLC to control the line. With the ability to adjust all powered line functions from either touch screen, the operator is free to focus on production and quality, without walking back and forth between control panels.
Incorporating the latest technology in electronics, microprocessors and software, Total System Control provides unsurpassed automation. State of the art programming allows coil stock to be threaded through the system without operator intervention, reducing complete coil changeovers to minutes.
The ServoMax TSC control package includes 999 job memory, feed length control, feed speed, passline height adjustment and straightener roll position set-up. Straightener roll position can be set automatically by inputting material thickness or by the selection of a preprogrammed job number. A built in Ethernet port is provided for real-time production monitoring of parts produced in a 24 hour period, analysis of jobs run, hit rate or spm for each job, uptime and changeover (downtime) between jobs.
Jobs can be selected locally at the ServoMax TSC control or via a communications port. Plug in option card capability for fieldbus options such as DeviceNet and ProFibus are easily installed.
The line is equipped with lifting entry/exit cascades with polyurethane rolls, four full-width chrome finish feed rolls, precision gear reduction, automatic central lubrication, handwheel adjusted self?centering edge guides and fixed height cabinet. The line features a "bow-tie" type shear with four-edge carbon steel blades, box-type gib frame design, pivot base for precision alignment, hydraulic power unit and integral mounting with the feed unit. Systems may also be designed with mechanical shears if higher production rates are desired. With the mechanical shear, the feed roll unit is synchronized with the shear as the line speed dictates, providing for a smooth operation and less wear on the clutch break system of the shear. If even higher production rates are required, a flying or a rotary shear may be specified.
Automated stacking and pallet discharge
The line features a hydraulic lift platform w/powered conveyor to discharge full pallets.
The stacker is equipped with adjustable side guides and end stop. The side guides and end stop are manually adjusted and are provided with scale and pointer for positioning. An auto-positioning feature for side guides and end stop provides simple adjustment based on part width and length.
This particular stack station is equipped with C-frame/90 degree rotating side supports that drops sheet directly down at the completion of the shear cycle. Other types of stacking stations are also used depending on line speed, stack width, material thickness and material surface.
The pallet end discharge conveyor will accommodate one full pallet plus one in the stacking station. The powered conveyor is operator-activated with pushbutton controls. Lines can also be equipped with side discharge depending on material flow in the plant.
The pallet staging station will accommodate one empty pallet for a staging station. The operator manually inserts pallets into the stacking position. Automated system can be provided if pallets are uniform in size. For even higher productions a pallet inserter can be incorporated with the stacker. The pallet inserter will insert pallets while the lift table is lowering to allow the line to run in continuous mode. Once the first pallet has been discharged the lift table is raised and the pallet inserter is removed.
Optional equipment may also include an edge trimmer to trim the coil to width before it is cut to length. This operation is typically preformed in previous processes but can be done in a blanking line. If done in-line, the edge trimmer would be located after the straightener/leveler just prior to the looping pit. The edge scrap is taken from the line and can be chopped, wound or balled.
While this article covers the basic parameters and equipment considerations of a blanking line, there are numerous ways to configure these systems to maximum accuracy and high productivity.
For more information regarding CWP blanking line system solutions, call 1-800-247-2645.
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