Why Plastics Industry Feed Screws are Designed the Way They Are

Download the white paper here.

The selection of the proper screw for a given injection molding or extrusion application can be critical to its success.

Screw geometry — length-to-diameter ratio, profile, channel depth, compression ratio, helix angle and a host of special design features — has everything to do with how well the screw performs in a given application.

There are documented applications where customers have improved production rates or reduced cycle times by 30 or 40% simply by switching to an improved screw design. Similarly, reject rates have been lowered from more than 4-6% to less than 1% by incorporating a custom designed mixing screw.

And experience shows that the amount of color concentrate required to achieve optimum color mix can be typically reduced from 4% (of the total blend) to 2%, just by using an optimized screw design. When considering resin and concentrate costs, payback for an optimized screw and non-return valve design can be almost immediate.

This white paper, published by Glycon Corporation, provides an in-depth look into plastics industry feed screw design.

DOWNLOAD THE WHITE PAPER FROM THIS AP CORP WEB PAGE

Vibration Control Systems from Crystal Instruments and AP Corp.

Crystal Instruments designs, produces, sells, and services hardware and software for machine vibration monitoring, dynamic measurement and environmental testing. The CoCo and Spider instruments have been widely used in machine condition monitoring and diagnostics by taking and analyzing the vibration signals. In the testing lab, professionals use Crystal Instruments products to conduct the measurement and control for vibration, shock, acoustic, pressure, temperature, humidity and other physical quantities.

AP Corp. applies, specifies, and supports the sales of Crystal Instruments products in Connecticut, Massachusetts, Vermont, Rhode Island, New Hampshire, and Maine.

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DOWNLOAD THE VIBRATION CONTROL SYSTEMS BROCHURE HERE

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AP Corp.
https://a-pcorp.com
(508) 351-6200

Occupational Health & Environmental Sound and Vibration Meter: The SVAN 977A

The SVAN 977A is a class-one sound and vibration level meter that offers unprecedented state-of-the-art technology designed for general acoustic, occupational health,  and building acoustic measurements of  vibration and environmental noise. The instrument comes equipped as standard with the SV7052E polarized half inch microphone, the SV12 microphone preamplifier, and the SA22 foam windscreen, as well as a large 16 gigabyte internal memory which can be easily upgraded by a micro SD card. The meter comes equipped with a standard quarter inch photographic thread. On the bottom panel you can locate the usb serial and I/O sockets. There is also a micro SD card slot under the bottom cover and spaces for the four double a batteries. The SVAN 977A is equipped with a super contrast led color display. The instrument's user interface makes both configuration and measurement easier than ever before. The user can easily operate the instrument by selecting the appropriate position from the selected menu lists.

The instrument has 2 general modes of operation: Configuration mode; and measurement performance and results preview mode. The SVAN 977A can be used in the meter mode to perform the real-time 11 octave or 1/3 octave analysis including calculations of statistical levels, and can also perform FFT analysis.  For building acoustic applications SVAN 977A offers reverberation time measurements RT60 and building acoustics assistant application for smartphones.

With a special microphone the meter provides measurement range of the ultrasounds up to 40 kilohertz. Measurement results can be viewed indifferent view modes, the set of which you can change and activate depending on the selected measurement function. If you disconnect the microphone preamplifier, you can use the instrument to take vibration measurements simply by connecting a cable and a vibration sensor.  SVAN 977A can be easily installed into the SM277 case and used as an outdoor monitoring station thanks to a dedicated modem station which enables connection to the SVAN NET, an advanced server solution supporting remote connection giving users full access to the measurement data via web browser or dedicated application.

For more information, contact AP Corp. by visiting https://a-pcorp.com or by calling (508) 351-6200.

The Three Most Common Types of Temperature Sensors

Various types and styles of temperature sensors (Pyromation).

This post describes the three most popular temperature sensors, how they function, and where they are used.

THERMOCOUPLES

Thermocouple illustration showing base metal designs
with various types of junctions (Pyromation).

Thermocouples are temperature sensing devices that operate on a phenomena called the Seebeck
effect. In the simplest terms, thermocouples produce a micro-voltage between two conductors - joined at each end and made of dissimilar metals - when one junction varies in temperature and the second junction (called the reference junction) is known and maintained at a constant temperature. The corresponding voltage produced at the sensing junction can be measured and directly correlated to the change in the sensing junction's temperature.

Thermocouples are popular and widely used in industrial and commercial temperate systems because they are:

• Cost-effective.
• Provide good accuracy.
• Have a sufficiently linear temperature-to-signal output curve.
• Are available in many different metal alloys for many different temperature ranges.
• Are easily interchangeable.

Thermocouples require no external power source to work and can be used in continuous temperature measurement applications from -185 Deg. Celsius (Type T) up to 1700 Deg. Celsius (Type B).

Thermocouples are commonly found in many industrial processes. Examples are the plastics industry, primary metals, power generation, kilns, industrial boilers, HVAC, gas turbine exhaust systems and and diesel engines. And because they are affordable and easy to produce, thermocouples are also used in many consumer applications, such as residential and commercial cooking and heating equipment.

RTDs

Wire wound RTD
(Image courtesy Wikipedia)

Resistance Temperature Detectors, referred to as RTD’s, are temperature sensing devices that determine temperature based on a relative change in resistance of the sensing element. The sensing element is a wire or etched circuit made from a metal with a well established resistance to temperature curve, most commonly platinum, nickel, or copper.  Platinum, nickel and copper are used because they produce a predictable and stable change in resistance as the temperature changes. Normally the wire is coiled around a bobbin (made of glass or ceramic), and inserted into a protective sheath. Alternatively, RTD's can also be manufactured as a thin-film, etched element with the pure metal deposited on a ceramic base, very similar to the way a printed circuit is made.

RTD’s are popular because:

• They offer considerably higher accuracy and repeatability than thermocouples.
• Can be used up to 600 Deg. Celsius.



Thin-film RTD
(Image courtesy of Wikipedia)

• Can be integrated directly on the part to be monitored.

They are used where accuracy is important, such as in biomedical applications, semiconductor processing and temperature critical industrial applications. They tend to be higher priced than thermocouples because they are made of pure metals, and they do need an excitation voltage from an external source for the device to be read.

THERMISTORS

Another very common temperature sensing device is the thermistor. Thermistors are also a resistance measuring device similar to RTD’s. However, instead of using a pure metal as the resistance element, thermistors employ a very inexpensive polymer or ceramic resistance element. While these materials are very cost-effective, the downside is the resistance-to-temperature output curve. The change in resistance to a corresponding temperature change is very non-linear, and as such, make thermistors' use practical only within a narrow temperature range.

Thermistors are very inexpensive and have a very fast response making them very attractive in applications where a narrow sensing range exists and cost is important. Thermistors also come in two varieties, PTC, or positive temperature coefficient, and NTC, or  negative temperature coefficient. PTC's resistance increases with increasing temperature,  while NTC's resistance decreases with increasing temperature.

Thermistors are used widely in food processing in digital thermostats, and for on-board temperature monitoring of electronics and circuit boards. They are also used widely in many consumer appliances.

For more information on any temperature sensing application, contact AP Corp and discuss your requirement with one of their experienced application experts. They can be reached at (508) 351-6200 or visit them at https://a-pcorp.com.

What are Plastics Industry Feed Screws and How Are They Made?

Feed screw maintenance.

Plastics industry feed screws, or feed screw augers, are mechanisms that use rotating helical screw blades to move plastics pellets through the barrel of molding and extrusion equipment. The feed screw transports the plastic as it changes phase from solid to viscous liquid through friction, shear, and conductive heat transfer. 

A typical feed screw has three zones. Plastic pellets enters the screw feed section where the pellets are compacted and conveyed. Next is the transition (or compression) section, where the plastic is compressed, conveyed, and melted.  Finally, the liquid plastic moves to the metering section where it is precisely controlled at optimum temperature and viscosity.

For more information about feed screws, or any part of the injection molding process, contact:

AP Corp.

https://a-pcorp.com

508-351-6200

Diagram of injection molding process.

An Introduction to Sentek Dynamics Vibration Testing Systems

Download the full paper here.

Whether you are shopping for your first shaker system, or just educating yourself on vibration and shaker technology in general, you'll find this white paper on Sentek Dynamics shakers helpful. Sentek Dynamics supplies vibration test equipment to reproduce real-world environmental conditions for global manufacturers and offers technology capable of reproducing a wide-variety of test requirements - vibration (sine, random, shock, SoR, RoR, RSTD and others), data recording and dynamic signal analysis.

Although this paper focusses on Sentek Dynamics products, it provides excellent details about shaker technology in general.

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Get the full Sentek Dynamics Vibration Testing Systems Introduction paper at this AP Corp. web page.

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Three Types of Common Industrial Sensors: Inductive, Capacitive, and Photoelectric

Three common industrial sensors are inductive proximity sensors, capacitive proximity sensors, and photoelectric sensors.

Inductive sensors can detect a target from 0.5 millimeters to 40 millimeters. They only detect metallic targets and therefore use a magnetic field to detect presence when a ferrous metal enters the magnetic field.

Capacitive proximity sensors on the other hand can detect dielectric materials such as liquids plastic glass, wood and granulated substances as long as it has a dielectric constant of 1.2 or more. Their range is from three millimeters to 15 millimeters depending on the dielectric material to be detected.

Photoelectric sensors have the greatest detection range from one millimeter to 25 meters or more. They operate by the use of an emitter which transmits a beam of light to the receiver. They operate by detecting the presence, or absence, of a light beam sent from transmitter to receiver.

These are three very basic sensor technologies used in many common applications. The video above provides an elementary understanding of the operational differences.

For more information on any industrial or OEM sensor, contact AP Corporation by visiting https://a-pcorp.com or by calling 508-351-6200

The SVAN 971 Class 1 Sound Level Meter

The SVAN 971 is a Class 1 sound level meter and real-time analyzer. It is an ideal choice for industrial hygiene noise measurements, short period environmental noise measurements, acoustics consultancy surveys, technical engineers dealing with noise issues, and general acoustics noise measurements.

The SVAN 971 is an extremely small instrument with options for 1/1 & 1/3 octave analysis. The instrument brings unprecedented state of the art technology to a SLM of this size.The user interface makes both configuration and measurement easier than ever before. For those who don't have time to work with measurement settings, SVAN 971 offers extremely simple operational mode with Start/Stop. Another exceptional feature is built-in self-vibration monitoring providing information about level of vibration that influences the measurement results.

For more information, contact:
Andruss-Peskin Corporation
https://www.a-pcorp.com
(508) 351-6200