Accuracy and Pharmacutical

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Accuracy and Pharmacutical

Solution Weighing Team

Why is accuracy / precision important ?

Knowing the error of your results helps

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To avoid Under/Overfilling

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Ensure product and human safety

Weighing within defined tolerances all the time

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Ensures certain quality standards

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Ensures stable production process

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Ensures reproducible production

Use Qualified Equipment (DQ, IQ, OQ, PQ)

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Traceability, Required for GMP

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What is Resolution

The weighing range divided by the display readability gives the scale resolution.

A quality scale has a high resolution and is very accurate at the same time.

The resolution of a quality scale is certified by Weights & Measures institutes (e.g. PTB).

A certified resolution is also called “approved resolution” and can be used for legal for trade.

A high readability automatically results is a high resolution but does not automatically result in high accuracy.

This relationship can be affected by different scale technologies.

Resolution = Capacity = 150 kg = 15,000d

Readability 0.01 kg(d)

What does resolution mean to you ?

You need to consider the resolution of a scale when you are worried about:

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Weighing errors

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Legal for trade applications

8Resolution need to be approved by Weights & Measure

8Ensures that result has certain accuracy

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Stability of displayed weighing result

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Ambient conditions

8Wind

8Temperature

8Vibrations

How can you technically influence the resolution ?

8Scale technology (Stain Gauge / Electromagnetic force compensation)

8Indicator

High resolution does not always mean high accuracy

Approved Resolution

Notified bodies certify scale accuracy related to scale class

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Certified resolution is indicated with “e” (difference between two display steps “d” following each other

Certified or approved scales can only display the „e“ value

For legal for trade applications, scales have to be certified in the EU and US.

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EU / OIML

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US / NTEP

7,5

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3 kg

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Benefits of Approved Resolution

Approved resolution “e” certifies scale accuracy

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Confirmed by Weights & Measures Institutes (Notified body)

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Approved or certified resolution “e” is the true value

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Displayed resolution “d” can be anything and does not inform about scale performance

Different scale classes indicate scale performance

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Typical classes use for industrial weighing applications

8Class II => High precision

8Class III => Medium precision

Display value “d” is just a dummy value

Cap.3 kg

Class II 10,000e and 100,000d

Readability=3,000g/(10,000e-100,000d) = 0.5g -0.05g

Typical Certifiable Resolution of Scales

Class II scales can have different certifiable resolution ranges

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From 5000e up to 60000e (Single range, delta range, e=10d)

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Typically within a temperature range of 0-40°C

Class III scales can have different certifiable resolution ranges

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Standard: 1x3000e (e.g. 30 kg scale => 0-30kg / 10g, e=d)

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2x3000e Multi-Range (e.g. 30kg scale => 0-15kg / 5g, 15-30kg / 10g )

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2x3000e Multi-Interval (e.g. 30kg scale => 0-15kg / 5g, 15-30kg / 10g )

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3x3000e Multi-Range/Multi-Interval)

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1x7500e (e.g. 30kg scale => 0-30kg / 5g, e=d)

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Typically within a temperature range of -10 to 40°C

Precision scales ensure high resolution within large

temperaure range

Typical Errors according OIML

OIML states maximum allowed error

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What is precision?

The degree of agreement between repeated measurements of the same quantity. The numeric value of precision is normally expressed as the result of the calculation of the standard deviation.

Precision can also be expressed as repeatability (reproducibility).

Precision depends only on the size of the differences observed while repeatedly weighing the same object and it is not concerned with freedom from error of the final result.

What does precision mean to you ?

You need to consider the precision of a scale when you are worried about:

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Reproducible and stable production

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Ensure similar batch quality

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Major influence of weighing tolerances of low quantities on big scales

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Same weighing result regardless on what area of the scale the product is placed

8Reducing operating errors

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How can you technically influence precision ?

8Scale technology (Stain Gauge / Electromagnetic force compensation)

8Direct force weighing technology / Lever weighing system

High precision does not always mean high accuracy

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1 What is corner load error?

Cornerload refers to the ability of an instrument to deliver the same weight reading for a given object anywhere on the weighing pan.

Scale technology has a major influence to corner load errors.

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Linearity refers to the quality of delivering identical sensitivity throughout the weighing capacity of a balance or scale. Test this characteristic by weighing two stable objects separately, each of approximately one half the weighing capacity. The sum of the two readings should equal the reading obtained when both objects are weighed together.

What is Linearity Error?

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3 What is Hysteresis error?

Property of load cells, and other weighing systems dependant on elastic materials, such as spring balances, resulting in a different indication at the same load, depending upon the direction of approach to that load, i.e. whether it is approached by increasing the load or decreasing the load.

What is Accuracy?

The degree of agreement between the result of a measurement and the true value of the quantity measured.

The sum of all individual scale errors are relevant for the accuracy of a scale and therefore also for its weighing certainty.

Corresponding to the international guidelines of the EC and the OIML, there are different classes of scale in order of increasing accuracy defined in the EC directive 90/384:

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Class I Special (e.g. high precision balance)

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Class II High (e.g. high precision industrial scale)

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Class III Medium (commercial scale)

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Class IIII Ordinary (e.g. high capacity scale)

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What does accuracy mean for you ?

You need to consider the accuracy of a scale when you are worried about:

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Over/Underfill of product

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Product safety

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Minimizing operating errors

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Weighing Speed

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Weighing of light and heavy products on same scale

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Changing ambient temperatures

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Quality of your weighing in general

Accuracy is defined by scale and sensor technology

Sensor Technology

Strain Gauge technology

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A metallic or semiconductor material of small cross sectional area that is bonded to a surface and elongates or contracts with that surface. This deformation results in a change in its electrical resistance, providing means for subsequent measurement.

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Used for most electronical scales (e.g. bathroom-, kitchen, supermarket- and

industrial scales)

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Strain Gauge Benefits

Economical sensor with acceptable accuracy

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Typically 3000e-7500e resolution

Large range of capacities form gram to several tons

Rugged and robust

Flexible use for many different scale types

Easy to service

Due to analog interface universal connection to terminals

Cheap technology for mass production

Sensor Technology

Electromagnetic Force Compensation (Monobloc)

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The principle of EMFC is based on the electrodynamicconversion principle. The Monobloc consits of a high-strength aluminium alloy. A complex pattern is eroded out of the compact block.

High quality technology for high precision weighing

Weigh scale sensors based on the EMFR principle are typically 10–1000 times more accurate than strain-gauge-based industrial load cells and other devices based on the measurement of deformation.

Monobloc Benefits

High precision sensor with high accuracy

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Up to 60000e approved resolution

Internal calibration

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Ensures scale performance

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Required for GMP

Digital communication

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Easy maintenance due to plug & play scale-terminal connection

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Weight is generated in weighing cell

8Less electical noise disturbance during data transmission

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Scale Technology

In addition to the weighing sensor, the scale construction has a major influence to the scale accuracy.

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Precision / Repeatability

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Linearity

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Corner Load errors

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Stabilization time

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Hysteresis

Depending on the application various scale constuctions can be used.

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Single point direct force construction (e.g. bench scales)

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4-point direct force construction (e.g. large industrial floor scales)

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Single point lever force construction (high precision scales)

Mettler Toledo uses all construction types

Scale Technology – Single Point

Single point direct force construction

-Used with bench scales up to 600kg

-Standard accuracy type scales (Strain Gauge)

-High precision scales (Monobloc)

-1 loadcell per scale

-Capacity of loadcell is more or less similar to scale capacity

Strain Gauge Loadcell Monobloc Loadcell

Mettler Toledo uses all construction types

Benefits Single Point Scales

Main application: bench and portable

Large variation of different scales -Sizes

-Capacities (typically 3-600kg)

-Material (painted, galvanised, stainless steel)

-Different resolutions / Accuracy

-From IP44 to IP69k

-Hygienic designs

Simple design ensures easy service

Used in all type of industries

Analog and digital versions

Most frequently used scales for bench applications

BBA449-A15

PBA430-B60 PBA330

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Scale Technology – 4 Point

4 point direct force construction

-Used with floor scales

-Standard accuracy type scales (Strain Gauge)

-Sum of all loadcell capacities is higher than scale capacity (preload possible)

-Typically 4 loadcell per scale

Mettler Toledo uses all construction types

Benefits 4 point scales

Main application: Floor scales

Large variation of different scales

-Sizes

-Capacities (typically from 150-6000kg)

-Different resolutions / Accuracy

-From IP65 to IP68

-Hygienic designs

Simple design ensures easy service

Analog and digital versions

Most frequently used for floor scale applications

DNE…sk with raisable stainless

steel load plate

PFA574 PUA579

PTA455

Scale Technology – Lever System

Single point lever construction

-Used with bench and floor scales

-High precision accuracy (Digital strain gauge + Monobloc)

-Capacity of scale depends on lever system

-1 loadcell per scale

-2 loadcell capacities (15 and 32kg) for complete weighing range from 15 kg – 3 tons

Perfect technology for high precision applications

1.5 ton scale 15 kg loadcell Levers

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Benefits Lever Based Scales

Main application: Bench, portable and floor

Large variation of different scales

-Sizes

-Capacities (from 15-6000 kg)

-High readability (up to 3.2 Mio points)

-Excellent precision and accuracy

-High IP ratings

-GMP

Digital version

-Plug & Play installation (terminal/scale)

-Change of scale / terminal without recalibration

Excellent scales where accuracy is important

KE/ME 3000 with raisable loadplate

KCC / MCC 150 / 300s

KA / MA15s

Comparision – Bench Scales

Mobobloc technology is > 10 times more accurate

Comparision – Floor Scales

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Accuracy scale to Pharma process

5. Packaging 4. Tableting

2. Dispensing 3. Mixing

Courtesy Roche 1. API Synthesis

Dispensing: Where exact amounts count

High Resolution digital scales

Precision balances XP Line

Analog scales

Weighing indicators IND449, IND690, ID30

Formulation solutions Raw material identification Raw material weighing Courtesy Roche 5. Packaging 4. Tableting 2. Dispensing 3. Mixing 1. API Synthesis

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Weighing in the dispensing room

Weighing indicator IND690/690xx Portable scale either with indicator or hooked-up to the IND690/ 690xx or ID30 Bench scale hooked-up to the IND690/ 690xx or ID30 Floor scale hooked-up to the IND690/ 690xx or ID30 FormWeigh.Net application running on ID30 with connection of any three weighing systems

Weighing in the dispensing room

Easy to clean floor scale PUA579 600kg/100g High resolution bench

scale KCC 150kg/1g High resolution portable

scale KA 15kg/0.1g

IND690

Wired data exchange over CL, RS232, Profibus®DP or Ethernet Barcode scanner for product identification Product identification with RFID technology Wireless data exchange over

Bluetooth™ or WLAN

Weighing station #1 Weighing station #2 Weighing station #3

Printer

Mixing of API with excipients

Granulates / Pellets making

Mixing and granulation

Formulation solutions

Weigh modules for reactors, tanks, mobile vessels

Courtesy Roche 5. Packaging 4. Tableting 2. Dispensing 3. Mixing 1. API Synthesis Sieving and Drying

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For accurate weighing and material transfer

Converters and indicators

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IND130

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IND560

Platforms

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Full range of K-line high resolution platforms

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Full range of analog platforms

Weigh modules

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Ultramount

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Ringmount

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Flexmount KES1500 Flexmount Ringmount IND560 IND130 Ultramount Packaging, bottling Final product inspection

Packaging solutions

Checkweigers

Metal metectors and X-ray systems

Courtesy Roche 5. Packaging 4. Tableting 2. Dispensing 3. Mixing 1. API Synthesis

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Accuracy and Pharmacutical