Spectrometers

Furthermore, as color spectrophotometer systems are highly sensitive, plastics and injection molding quality control frequently takes place in laboratories away from the processing lines under the supervision of highly trained personnel, oftentimes requiring frequent recalibration, specific lighting and even physical contact with the measured part. And even in plastics factories where quality control is performed on the production line, existing color spectrometers are expensive, cumbersome, limited in their applications and do not perform in-line adjustments to the production process.

Optical Probes Used for Color Spectrophotometers

One of the primary detractors and limitations of the popular spectrometers available today are the optical probes used. Essentially, each probe is in effect its own spectrometer. A single spectrometer is associated with a single probe or test application, and multiple spectrometers are thereby required to test multiple parameters. As effective color quality control testing involves much more than just color, but also must consider haze, transparency and opacity, existing spectrometers have become a costly financial burden on the factories looking for a well-rounded solution for performing effective color quality assurance on plastics.

A New Color Spectrophotometer

To address the challenges of improving plastics color quality control and minimizing product rejects, while at the same time maintaining production efficiency (and minimizing the drain on masterbatch inventory), an Israel based company has developed a versatile color spectrometer that integrates within the production line and opens up the possibility of real-time analysis for all new plastic products.

The company’s patented in-line spectrometer can be placed at the molding machine or extruder for all types of plastics and films, and makes possible a range of high-demand and real-time QA applications including digital setting of the pass/fail criteria and in-line testing of product color.

The new color spectrometer’s versatility can best be expressed by its novel optical probes. For the first time, transmitted color, opacity, reflected color shade or haze can be measured simultaneously or separately according to quality control requirements, by allowing multiple probes to be simultaneously used, and enabling easy switching between probes within the spectrometer.

The company’s versatile spectrometer can also be operated in either differential, absolute, or detailed absolute modes, enabling measurement of new-product color differences with either a reference part or coordinated L*a*b*.

Finally, the new color spectrometer offers plastics manufacturers added value by enabling real-time analysis and in-line correction of masterbatch and color additive dosing quantities for 100% of machine cycles by communicating with the additive feeder or other plastics auxiliary equipment.

Advantages of a New Multi Probe Spectrometer

The new multi-channel spectrometer is able to process data from multiple probes simultaneously. Unlike existing spectrometer manufacturers which use a single spectrophotometer device per optical head, this versatile spectrometer connects with multiple optical probes; enabling a faster QA process, greater efficiency and unmatched cost savings

By enabling multiple probes to be used simultaneously, plastics manufacturers can now compare new pieces to a reference piece, or to a data reference in a color library. Of particular value, quality control engineers can now simultaneously test multiple locations on the same product.

Highest Level of Accuracy and Functionality in a Color Spectrophotometer

One of the known shortcomings in color spectrophotometers for quality control applications are the factors which can alter the readings of the spectrometer. Changes in lighting, dirt, angle of the probe or distance from object may all effect the sensitivity of the probe output. As plastics manufacturing is overwhelmingly associated with dirty factory floors, (short of medical grade equipment where cleanliness is mandatory), existing spectrometers are limited in their accuracy by dirt which often finds its way to the optical lens. For this reason, the majority of existing handheld spectrometers require frequent calibration, and must be placed directly on the object, or performed in a laboratory.

A major benefit of the new compact spectrophotometer is that it offers plastics factories the easiest maintenance of any color spectrophotometer instrument, as calibration is easily performed with a simple white balance. Easy calibration will save companies many hours of down time and expensive labor associated with maintaining specialty equipment.

Furthermore, the ability to operate in dirty environments is one of the stand-out features of the new color spectrometer.

The optical lens and probes used in the new color spectrophotometer includes a small form factor, while the patented optical design makes the probes impervious to distance, surface texture, and lateral or angular positioning. This design also gives the color spectrophotometer high stability and durability.

Finally, the new color spectrometer offers several impressive features for quality control engineers.

The game changing technology made available in the new compact spectrometer allows factories to speed up production, improve plastics quality control and minimize masterbatch and color additive material consumption to the absolute minimum necessary; resulting in significant cost savings for plastics factories and a significant edge over their competition.

In instances where the product is small, and only a few granules of masterbatch are fed into the batch, a small dose loss-in-weight gravimetric feeder can be used. The manufacturer of the new color spectrometer also manufacturers a novel loss in weight gravimetric feeder that obtains the highest possible dosing precision by utilizing a novel vibrating channel.

Integration with Real-Time Masterbatch Shade Production

By being able to automatically monitor color shades, and make adjustments in real time to the blending system, the new spectrometer makes possible one of the biggest breakthroughs taking place now in plastics manufacturing.

Until now, masterbatch producers would supply plastics manufacturers with the required masterbatch color shades necessary for all of their products. In a medium sized factory, this can easily amount to 500 different shades that must be held in inventory, while a large factory may hold as many as ten thousand different masterbatch shades. As masterbatch is by far the most expensive component of all the raw materials used during production, this setup of holding large inventories of masterbatch constitutes a considerable cost to manufacturers relating to logistics and warehousing.

The manufacturer of the color spectrometer has developed a fully automated and simultaneous multi-channel weighing and mixing system for producing new homogeneous masterbatch shades from an inventory of primary masterbatch color shades and additives. By simultaneously weighing all materials with resolution of a single pellet, the new blending systems significantly reduces production costs associated with manual labor.

The new masterbatch shade system is an 8-14 bin blender that allows large plastics manufacturers to create any masterbatch shade by combining primary mono masterbatch shades together. However, the key to making this system possible is the new color spectrometer.

The color spectrometer is used to scan a desired masterbatch shade, which is translated by into the masterbatch blending system into a formula for combining the primary masterbatch shades in order to reach the original shade. After the blender combines the masterbatch shades, and passes it through an extruder, it is measured again by the spectrophotometer to determine that it is the correct shade. In-line adjustments are then performed as needed.