Important terms from process technology
Alarm (Alarm Limit)
An alarm limit is a limit in the domain of the monitoring. An alarm is released, as soon as a monitoring function crossed an alarm limit. An alarm marks the produced part as a bad part, because it does not comply with the required quality characteristics (which are defined by the monitoring limits). Such a part is automatically sorted out. See "Separation of bad parts"
An analog signal is, within the context of the signal theory, a form of a signal with continuous and interruption-free course.
Modular hardware of the PRIAMUS FILLCONTROL platform. It provides the amplifier modules type 5080, type 5070, the Core with display type 8280 as well as the I/O modules Master type 8980 and Expander type 8981, Bus Interface type 8982 and the Voltage Input Module type 8983.
The BlueLine amplifier type 5080 is a measuring amplifier for cavity pressure and mold wall temperature with 4 or 16 channels each. It is part of the universal PRIAMUS BlueLine data acquisition system for intelligent monitoring and control of the injection molding process. Due to its modularity, the BlueLine Amplifier Type 5080 allows individual configuration of the user system.
The BlueLine Amplifier Type 5070 is a measuring amplifier for cavity pressure and cavity temperature with 2 measuring channels for pressure and temperature measurements.
BlueLine Bus Interface
Coupling module between the Top Hat Rail Set and the Hybrid Bus cable for BlueLine devices. The Bus Interface type 8982 is used for connecting an I/O module chain (consisting of an I/O Master and one or several I/O Expanders) to the Hybrid Bus Cable Type 1280.
Powerful control device for monitoring, open- and closed-loop-control of the injection molding process according to state-of-the-art. Type 8280 with Touch Screen and integrated FILLCONTROL software.
BlueLine Hybrid Bus Cable
The hybrid bus cable type 1280 is a connecting cable for the connection of all BlueLine devices (amplifiers, Core and I/O modules).
BlueLine I/O Expander
Expander module for digital switching signals (inputs / outputs). It transmits control signals from the injection molding machine to the BlueLine system (Input) and receives such signals from this system (Output). The first I/O Expander is directly connected to the I/O Master (via Top Hat Rail Set). You can add additional I/O Expander modules via plug and play via Top Hat Rail Set.
BlueLine I/O Master
The I/O Master type 8980 is a base module for digital switching signals (inputs / outputs). It transmits control signals from the injection molding machine to the BlueLine system (Input) and receives such signals from this system (Output). Depending on your needs, you can connect one or several BlueLine I/O Expanders or Bus Interfaces to the I/O Master.
BlueLine Voltage Input Module
The BlueLine Voltage Input Module type 8983 for the acquisition of 8 analog voltage signals (e.g. 24 V machine signals).
Capability (Process Capability)
Process capability defines how good a process, respectively, how the results (output) match with the (customer) quality requirement. The shown process capability, respectively, process control charts are used as process documentation. They help the injection molder to draw up his production based on key figures from the cavity. By using this, process fluctuations, thermal balance, shutdowns etc. can be visualized easily and understandably.
Cavity Pressure Sensor
PRIAMUS Cavity Pessure Sensors are used for industrial monitoring and controlling of injection molding processes. For decades sensors of this kind and dimension have been used to determine, even during production, the physical properties of a molded part and to adapt them as necessary. The piezoelectric measuring technology has become established for this application over the years, because the sensor itself is especially suitable for this. On account of the partial very fast injection processes, requirements are developed which can only be fulfilled by very compact and stiff sensor designs. PRIAMUS reference in particular to the internal and patented protected developments PRIASAFE® and PRIASED®.
The cavity temperature is (during continuous production) above the mold temperature. The cavity temperature can be measured by, in the cavity (wall) mounted, sensors. The temperature varies because of heating (injection phase) and cooling (back pressure and cooling phase).
Cavity Temperature Sensors
The term ‘cavity temperature’ was created with the founding of PRIAMUS SYSTEM TECHNOLOGIES AG.
PRIAMUS® Cavity Temperature Sensors have been especially designed to be used in the mold cavity. In this context the reaction time of the sensors play a vital role. Target is to detect the melt front practically in real time. Therefore, the sensor acts as a kind of light barrier in the mold. Furthermore, in this way the temperature profiles of each cavity or special areas of cavities can be analyzed. Therefore, the sensors serve the monitoring and controlling of injection molding process.
Input connection and / or output connection for a measured variable on the electric device, e.g. the charge signal of a sensor.
Cold Runner Mold
With coldrunner molds the melt solidifies in the sprue and is separated during or after the demolding of the component.
Communication interfaces are used to read and write actual and set values based on a communication protocol (such as Euromap, SPI or manufacturer specific protocols). This involves for instance injection speed profiles, holding pressure profiles or hotrunner nozzle temperatures. In principle all parameters defined in the protocol may be sent and received. Physically these data are being transmitted for instance to the hotrunner controller or to the host computer of the machine via interfaces such as e. g. RS-232, RS-485 or Ethernet.
Many molded parts are not made in the mold platen itself but with the help of mold inserts. This makes it easier to manufacture and maintain the cavities. The use of cavity pressure sensors and cavity temperature sensors is in this case often limited because of the available space. In addition the handling of cables with fixed installed sensors is work intensive during mounting and dismounting of the mold inserts. As a solution PRIAMUS® developed Compact Sensors for the pressure and temperature measurement in injection molds. Instead of connecting the sensors by a connecting cable with the coupling in the mold insert, the Compact Sensor is tightly connected via a distance sleeve with the coupling. In this way an extremely compact and very easy manageable solution is generated which is available in different dimensions depending on the application. The length of the Compact Sensors is variable and must be specified with the order.
The mechanical strength of a molded part depends on the compression of the melt during manufacturing. Depending on the application and the geometry of the molded part, too high compression as well as too low compression may lead to undesired results. In order to reproduce the compression of a molded part, the holding pressure profile of the machine must be adapted. For reproducing this determined and optimized compression initially one single parameter is being optimized. This parameter is adapted by the holding pressure profile of the molding machine until the optimized compression in the cavity finally is achieved.
Compression Injection Molding
The injection-compression is an injection molding process for the production of high precision or big components of plastic. Thereby the plastic melt is injected in the practically unpressured, not completely closed, mold. The mold is only completely closed during the solidification process. The thereby corresponding, steadily closing pressure guarantees the final molding of the component. By the help of the automatically detected melt front, the stamping process is initiated in relation to the volumetrical filling.
See "BlueLine Core"
Core Pull (Technology)
The core pull is a component of the injection molding machine. The core pull is a plunger (different designs) which can be retracted and extended in the cavity to enable a corresponding volume during the injection or to demould specific sectors. The controlling of core pulls is triggered by melt front detection. The core is always controlled at the same volumetrically full degree and not traditional via time, with the consequence of different melt positions.
Core Pull Control
The core pull control is a component of the injection molding machine to control the core pulls.
A digital signal is a map of an analog signal in time-discrete and value-discrete form.
The ejector pin is a component of the mold and serves the demolding of the molded parts. Note: There are also other demolding units such as stripper plates.
FILLCONTROL Event Log is displaying all messages generated by the system. Thereby the user is being continuously informed about the state of the system, in order to control and adapt those in an optimal way.
FILLCONTROL is the central data acquisition, evaluation and control software for all PRIAMUS applications. The FILLCONTROL software provides the user interface for PRIAMUS measuring devices.
FILLCONTROL FreeViewer Type 7080 is a free of charge software module for the display and analysis of FILLCONTROL measuring data.
FILLCONTROL Measure type 7080 is a free of charge software module for simple data acquisition and process documentation with BlueLine amplifiers.
FILLCONTROL Monitor type 7080 is a software module for individual monitoring and control of the injection molding process to be used together with the BlueLine Core type 8280.
FILLCONTROL Switch type 7080 is a software module for the controlling of injection molding processes as well as special switching and monitoring processes, for example in rotary table applications or in sequential injection molding.
FILLCONTROL Control H
FILLCONTROL Control H type 7080 is a software module for the balancing and controlling of hot runner molds, including BlueLine Core type 8280 and communicating cable.
FILLCONTROL Control P
FILLCONTROL Control P type 7080 is a software module for the controlling of shear stress, shear rate, compression and shrinkage via host computer interface of the injection molding machine, including BlueLine Core type 8280 and communicating cable.
FILLCONTROL Control V
FILLCONTROL Control V type 7080 is a software module for the balancing and controlling of the melt flow especially of cold runner molds (LSR). Thereby the opening times of the valve gate nozzles are automatically delayed, including BlueLine Core type 8280
Fill Time Control
On this control operation mode the melt flow is controlled on a reference state. This issue of time is fixed by the set fill time [period] in [s] at the beginning of each cycle. This fill time control can be carried out by nozzle temperatures as well as by the control of valve gate nozzles.
The flow path is the distance the melt needs to pass until the cavity is filled.
Flowpath-Wall Section Ratio
Relation between longest flow path of the mold, measured from the gate to the end of the flow path, divided by average wall thickness on this distance.
An improper installation of a pressure sensor (contact of measuring element with wall of the bore) produces a force shunt. This force shunt effects a loss of sensitivity of the sensor. The measurement will be distorted. Such an error may be up to 30 %. The smaller a sensor, the larger the influence. Each pressure measurement without PRIASAFE® technology is therefore dependent on the installed conditions of the sensor. For that reason, the measurement without PRIASAFE® technology is not necessarily reproducible and trustworthy.
Hardware interfaces are designed to transmit status information at certain events (e. g. "valve gate open“, "automatic switchover to holding pressure" or "separate reject part"). These events may be transmitted from the PRIAMUS® system to a machine, a robot or a peripheral device, as well as in the opposite direction. Physically and typically this involves a voltage level (e. g. 0 V / 24 V) which represents the logic status „0“ and „1“. In the future this will also be possible fully digital via a real time bus.
After injection the machine switches to holding pressure. The holding pressure and the holding pressure time should compensate the volume contraction during the solidification of the melt as much as possible.
Holding Pressure Level
Many machines offer up to ten holding pressure levels. In the case of thin-walled components, for example, a short high holding pressure level is followed by a lower holding pressure to avoid too high tensions near the gate.
Host Computer Interface
The interface of the host computer serves the communication with the single components of a machine and is needed for PRIAMUS® controlling with FILLCONTROL Control H / Control P.
Hot Runner Balancing
FILLCONTROL Control H can be operated in hot runner balancing mode. On this control operation mode for multi cavity molds all cavities should be filled simultaneously, i.e. different volumetrical degrees of filling in the cavities are balanced until a balanced state predominates. This module can be used for pure hot runner manifold applications as well as for sub-contributor with hot-to-cold applications.
Hot Runner Control
By the use of hot runner control the melt flow of hot runner molds is controlled.
Hot Runner Control Device
The hot runner control device controls the temperature of hot runner manifold and hot runner nozzles and influences therefore the melt flow in hot runner molds.
Hot Runner Manifold
The hot runner manifold is a component of the hot runner gating system. The hot runner manifold serves the distribution of the melt to the single cavities.
Hot Runner Mold
See "Hot Runner System"
Hot Runner Nozzle
The hot runner nozzle forms the transition between heated and unheated zone in a mold of an injection molding machine. The hot runner ends in the tip of the hot runner nozzle. Each nozzle features differences in sensitivities for heating and cooling processes.
Hot Runner System
The hot runner / hot runner system is a special design of the gating system in the processing of plastics. The gating system is thermally isolated and higher tempered in contrast to the remaining mold. Because of this, the plastic in the sprue stays constantly flowable. No sprue stays at the component.
Hybrid Bus Cable
See "BlueLine Hybrid Bus Cable".
Indirect Pressure Measurement
The indirect pressure measurement is mainly used where no sensor for direct measurement can be placed due to design reasons or where the witness of a sensor mark is not acceptable. This measurement is affected by friction (dependent on pin diameter) and may change over time due to deposits (abrasion).
Individual Separation of Bad Parts
Individual separation of bad parts assumes recognizing and differentiating of good parts and bad parts. Not the entire shot is separated, only the cavities of the bad parts. In this case the interface I/O Expander type 8981 is being installed at the corresponding handling.
Screw advance speed inside of the injection unit during the injection phase. The injection rate is regarded as the control value to influence the share rate [1/sec] of the molded part.
Injection Speed Steps
Length sections during the injection with different screw rates. Usually, at least 2 injection speed steps are used. The second step will drive through briefly and at a deeper injection speed to prevent overmolding with the switchover to holding pressure.
The integral shows the area under the corresponding measurement graph. The integral can be used as a monitoring function and can be time limited. For example, the integral of the pressure graph during the injection phase or the integral of temperature graph during the cooling phase are used as monitoring functions.
Intervention (Action Limit)
An action limit is a limit in the domain of the monitoring. An action signal is released, as soon as a monitoring function exceeds or drops below the action limit. The produced part is still a good part. The tolerances of the action limits are contained within the alarm limits. This function should be used to recognize a drifting process on time, to react before the alarm limits are crossed.
Liquid Silicone Rubber (LSR)
Liquid silicones are elastomers consisting of two components. The components are mixed directly before injection.
Machine Barrel Cylinder
The machine barrel is a central component of the injection molding machine. The screw is moving inside the machine barrel. More detailed information see “Screw”.
The machine control assumes the monitoring and analysis of machine data. By continuously monitoring and correcting the parameters the production process is stabilized and a maximum production efficiency is achieved.
The machine interface serves the communication and is an interface between physical systems.
The machine nozzle forms the end of the injection unit at the machine barrel. The machine nozzle serves the transfer of the melt from the injection molding machine to the mold.
FILLCONTROL monitoring criteria "Maximum value".
The melt flow over a specific distance is defined by the share rate. The controlling of the viscosity of plastic melt with FILLCONTROL bases on the calculating relationship shear stress / shear rate. A too high viscosity can be reduced by increasing of shear rate (or reducing shear stress). A too low viscosity can be increased by reducing of shear rate (or increasing shear stress).
Position of the melt inside the cavity. PRIAMUS is able to detect the melt position.
The melt temperature is generally defined as the average temperature of melt volume, in the collecting chamber between the nozzle and the tip of the screw, which is provided for the next shot.
Melt Temperature Sensor
A melt temperature sensor determines the melt temperature. See "Melt temperature"
FILLCONTROL monitoring criteria "Minimum value".
The mold temperature for each plastic material is indicated in a range and is a compromise between cost-effective production and optimum structural properties.
The controlling of a process is when an interaction takes place in which a principle variable (dynamic) size is kept automatically constant or roughly constant. Characteristics for the controlling of injection molding processes: The influence of the controlling must be measured directly at the molded part. Only then it is possible to speak from a closed control loop.
Dimension of the component after the demolding and shrinking (1 to 3 days after demolding according to the plastic type and wall thickness). On account of the shrinking the part dimension is smaller than the dimension in the mold.
Quick Disconnects make installing and removing of the tool inserts simple, quick and safe by the separation of the connection cable.
Quick Disconnect Cable
The Quick Disconnect cable is mounted in the mold platen and establishes the connection between the compact sensor, or sensor with quick disconnect, to the connecting cable or multi channel connecting box.
A sensor with a piezoelectric measuring element yields an electrical charge during mechanical deformation or under pressure. This electrical charge corresponds to the piezoelectric signal. By the indication of the sensitivity of each single sensor [pC/bar] the values of charge can be converted to pressure values and displayed as a cavity pressure curve.
The PRIAFIT® mounting sleeve for cavity pressure and cavity temperature sensors consists of a combination of mounting nut and distance sleeve and combines the advantages of both methods. The thread for the mounting of the sensor can easily be tapped near the borehole top and the length of the sleeve must not be cut exact but only approximate. A simple but very efficient and cost-saving method.
PRIAMUS procedure for safe mounting of cavity pressure sensors. These sensors are protected by a casing and a force shunt (after calibration) is avoided. Only this concept guarantees a reproducible measurement of pressure even after mold service.
PRIAMUS procedure for automatic sensor and sensitivity detection. Thereby the sensitivity is identified and processed by a built-in hardware code inside the sensor.
The process control is an approach for the automatic optimization of production processes.
A process is always subject to process fluctuations. The lower the process fluctuations are, the better the process is. By the monitoring and controlling functions of FILLCONTROL, process fluctuations are timely recognized, analyzed and minimized.
Process monitoring is a method of monitoring of production processes based on statistical procedures.
In contrast to online control this control refers to an open control loop, this means that no information is flowing back.
There is a great variety of rotary table constructions. They are used for multi-component injection molding or for injection molding parts with inserted components. Mold halves, for example, are displaced by a rotary table and the injection molding process is continued further on. Particularity of process monitoring and process controlling: The measuring channels and monitoring functions must be assigned to the corresponding rotary table position. Furthermore good and bad part signals might need to be sent delayed by x cycles.
The screw is located inside the plasticizing unit and has the following functions: absorbing granulate from hopper, conveying, compressing, melting, homogenizing and injecting.
The screw position, as well as the injection rate and the injection pressure, belong to the controlled injection molding machine parameters.
Screw stroke during various production phases.
Separation of Bad Parts
Separation of bad parts assumes recognizing and differentiating of good parts and bad parts. A good, respectively, bad part signal is transmitted above a standardized interface to the machine, respectively, to the robot (to the part separation), see als "Alarm".
Sequential Injection Molding
Sequential injection molding is a special kind of sequential valve gate closing. The optimal filling of a component can be carried out with the valve gate control, through individual opening of the valve gate nozzles in a graded sequence (based on melt front detection). A sequence running of the melt front is thereby generated from section to section.
Shear Rate Control
The shear rate of a plastic melt depends on the geometry of the cavity and on the adjusted injection speed of the molding machine. Basically two sensors are required to determine shear rate by which the arrival of the melt front is automatically detected at the sensor position. On principle two pressure sensors, two temperature sensors or one of each (pressure or temperature) could be used. The determined shear rate can be reproduced at any time on the same or on another machine by varying and adapting the injection speed profile accordingly. The flow conditions are therefore always the same.
Shear Stress Control
Shear stress is determined during injection and depends, first of all, on the fill pressure during the filling stage. For this reason the beginning of the pressure rise and the moment of pressure detection are automatically determined and analyzed. In order to control the shear stress the melt temperatures must be changed. This is done by changing the barrel temperature and, with hot runner molds, additionally changing the hot runner temperatures. The shear stress is often used when concerned about surface quality. Only via this value it is possible to make a statement regarding the reproducibility of a surface property.
See "Parts dimension" and "Shrinkage control"
Shrinkage control with FILLCONTROL Control P. A molded part starts to shrink in the injection process when atmospheric pressure is reached by cooling of the melt. If these parameters change during the process also the shrinkage of the parts (parts dimension) will change. The shrinkage control of the FILLCONTROL system determines the cavity temperature when reaching atmospheric pressure (or a certain residual pressure) and controls existing deviations automatically. The system controls the temperature controllers preferably via main computer interface of the machine.
The standard deviation is a term of the statistics and probability calculation. The standard deviation is a measure of the dispersion of the values of random variables around the expectation.
Switchover to Holding Pressure
While switching from injection pressure to holding pressure the machine is switching from the speed-controlled injection phase, in which the cavities are filled, to the pressure-controlled holding pressure phase, in which the shrinkage of the material is compensated. Ideally this switchover occurs exactly when the cavity is nearly filled volumetrically.
Temperature Control Unit
A temperature control unit is a device (as a part of a production plant) that carries out the tempering of a medium for the production process (mold).
A thermocouple converts heat into electric energy (thermoelectricity). It is a component made of two different metals connected with each other at one end. A temperature difference generates an electric tension by the heat flow. PRIAMUS® uses thermocouples Type N which offer certain advantages in contrast to thermocouples Type J and Type K.
Thermoplastics (plastomers) are plastics which can be deformed in a certain temperature range (thermo-plastically). This process is reversible, i.e. it can be repeated any number of times by cooling down and rewarming up to the melted state, unless the so-called thermic decomposition takes place by excessive heating and / or shear.
Thermosets are plastics which can no longer be molded after solidifying. Thermosets are hard, glass-like polymer materials that are linked in a rigid 3-D structure by chemical primary valency bonds.
Traceability is a term of measuring technology and analytical chemistry and describes a characteristic of measurement results. For traceable measured values applies: Each measured result can be referenced to national or international norms by a continuous line of comparative measurements with indicated measurement uncertainties.
Validation is the proof for repeatability of a result from a described approach under defined conditions. Machine parameters are used for the classical injection molding validation. Nevertheless, PRIAMUS uses the measuring data from the cavities. Only then is it possible to speak about process validation. Only if the process is repeatable, a constant part quality can be assumed.
Machines valve gates are used where dropping of melt or stringing of mostly low-viscosity materials should be prevented.
Valve Gate Control
The valve gate control controls (for example by pressure) the opening and closing of the valve gate(s). An automatic calculation of these switching processes (valve gate control) was realized with FILLCONTROL Control V.
The viscosity of a melt is a measure of the inner flow resistance. The viscosity is calculated from the quotient of the shear stress and shear rate and can be measured, monitored and controlled by Cavity Pressure Sensors and Cavity Temperature Sensors. Viscosity differences affect fluctuations in the process with the result of quality differences in the production.
A voltage describes the difference of electric potentials (different electric load). Injection machines deliver different status signals in the form of analog voltages. These signals can be analyzed, compared with measured data from cavities and monitored by help of FILLCONTROL.
The volumetric filling is reached when the cavity is filled. Before reaching of the volumetric filling (approx. 95 – 98 %) the switchover from injection pressure (injection rate) to holding pressure is carried out.
A warning limit is a limit in the domain of the monitoring. A warning signal is released, as soon as a monitoring function exceeds the warning limit. The produced part is still a good part. The tolerance of the warning limits are contained within the action limits. A warning signal can be seen as the first sign of a drifting process.