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Tuesday, August 25, 2009

Tape Test

Question:
Need a simple method that will aid visual inspection?

Answer:
The Tape Test is a simple method that aids visual inspection and is well suited for testing the cleanliness of smooth metal and plastic parts. It involves attaching transparent adhesive tape to the surface being measured, firmly pressing it down, carefully removing it and then placing it on a sheet of clean white paper. Visually comparing the sample with an adjacent piece of white paper is a fast, easy way to monitor particulates and sometimes even film residues.

Need to get your hard surfaces cleaner? Alconox, Inc manufactures a range of aqueous critical cleaners from acid to alkaline, powder to liquid, highly emulsifying to low foaming. Brands are available globally with consistent formulations and are GMP compliant. Certificates of analysis, technical bulletins, MSDS, trace analysis, and inhibitory residue testing are downloadable from the Alconox website.

Friday, August 21, 2009

Measuring Cleanliness - Low Tech Detection Methods

Question:
What low tech and easy to perform detection methods can be used to measure cleanliness at 0.01 grams per square centimeter?

Answer:
Visual inspection is best used to detect residues of contrasting color or texture. Good lighting can enhance visual inspection. Magnification and fiber optic lighting, which throws light across a surface, improve detection.

Low-power microscope inspection is a quick and efficient way to verify cleanliness of residual oils and greases, flux residues, particles and surfaces.

Wiping with a white wipe provides a contrasting surface with which to detect dark residues (the white glove test).

For more information on how to measure cleanliness, request a free copy of The Aqueous Cleaning Handbook. Entire chapter dedicated to Measuring Cleanliness! To get your FREE copy, simply email request to cleaning@alconox.com.

Thursday, August 20, 2009

Methods for Measuring Cleanliness

Question:
What methods can be used to detect cleanliness at 0.01, 0.01 to 0.001, and below 0.001 grams of soil per square centimeter?

Answer:
Depending upon method selected, cleanliness can be detected to varying degrees or levels.

Cleanliness can be detected to 0.01 grams per square centimeter levels by using visual inspection, low power microscope inspection, wiping and visual inspecting, water break tests, atomizer tests, nonvolatile residue inspection, surface UV Fluorescence detection, tape test.

The level of cleanliness typically suitable for automotive, aerospace, electrical and many surface preparations is between 0.01 to 0.001 grams per square centimeter. This level of detection can be achieved through Millipore filter measurement techniques such as optical microscopy, extraction, oil evaporation, oil soluble Fluorescence, gravimetric analysis, surface energy tests, contact angle measurement, particle counting.

The highest level of cleanliness measurement, below 1 microgram per square centimeter, is suitable for use in semiconductor, disk drive, and medical device applications. Techniques that are used for this level of precise cleanliness measurement include carbon coulometry, electron spectroscopy for chemical analysis (ESCA), Fourier transform infrared (FTIR), Gas chromatography/mass spectrophotometry (GC/MS), Ion chromatography (IC), Optically stimulated electronic emissions (OSEE), Particle counting, scanning electron microscopy (SEM) and Secondary ion mass spectroscopy (SIMS).

Need to get your surface cleaner? Need help selecting an aqueous critical cleaner to best meet you critical cleaning needs? The Critical Cleaning Experts at Alconox, Inc. can help, click here to “Ask Alconox”.

Thursday, August 13, 2009

Cleaning parts with complex geometries

Question:
What is the best way to clean parts with complex geometries such blind holes so that optimal cleaning is achieved?

Answer:
When cleaning parts with complex geometries, you should pay particular attention to any blind hole that can trap air, particles or cleaning solution during the cleaning and rinsing process. Air trapped in a blind hole interferes with cleaning and rinsing. Blind holes that face up and trap solution can potentially trap particles and cleaning solution that would otherwise rinse away if the hole was able to drain. To clean a blind hole, you need to make sure that cleaning and rinsing fluid gets in to the hole and back out. If blind holes are all on one axis of a part, and you are cleaning under immersion such as with ultrasonics, then one way to assure this is to put the parts in with the blind holes horizontal so that they fill up with solution and release any trapped air, then under immersion, rotate the part so that the blind holes face down, which allows gravity assisted release of any particles or residues that are removed during the process. Reverse the process to remove the part from the tank to allow the cleaning solution to pour out from the blind holes in a horizontal position. Repeat for immersion rinsing, or better yet, rinse with running water being sure to flush the blind holes. If a part has blind holes on multiple axis, then for immersion cleaning, you would want to rotate the part under immersion in order to release all trapped air and fill the holes with cleaning solution. If practical, it is desirable to further rotate the part during cleaning to pause for a period of time so that each axis of blind hole faces downwards for part of the cleaning cycle. In some cases it can even be worth creating a basket or bracket system that continually rotates the parts during cleaning and rinsing if rinsing is done under immersion. For spray cleaning of parts with blind holes, you want to pay attention to the orientation of the spray to make sure it penetrates and flushes the blind hole during cleaning and rinsing.

Alconox, Inc manufacture’s a range of aqueous critical cleaners from acid to alkaline, powder to liquid, highly emulsifying to low foaming. Brands are available globally with consistent formulations and are GMP compliant. Downloadable certificates of analysis, technical bulletins, MSDS, trace analysis, and inhibitory residue testing are available from the Alconox website at Alconox.com.

Friday, August 07, 2009

Title: Standard Operating Procedure (SOP)

Question:
Can Alconox, Inc provide an example of a standard operating procedure for cleaning glassware?

Answer:
The following is an example of a standard operating procedure (SOP) for cleaning a glass substrate:

To clean glass substrates: Make a 1% solution of Alconox detergent (10 g/L) in hot (50 deg C) deionized water in an ultrasonic tank. Remove glass from supplier packaging. Place the glass in a rack and immerse for 5 minutes. Rinse for 1 minute under running deionized water making sure to contact all parts of the glass for at least 10 seconds. Dry for 2 hours in a drying oven with HEPA air filtration. Allow cooling to ambient temperature for 20 minutes in a clean bench before use.

To download an Alconox technical bulletin click here

Thursday, August 06, 2009

Standard Operating Procedure (SOPs) For Cleaning

Question:
What are important items to include in standard operating procedures for cleaning?
Answer:
A large part of successful cleaning relies on having a sound, reproducible procedure. In general, a good SOP should present a list of materials and people involved, the surface being cleaned should be identified, and the eight key variables for cleaning effectiveness should be defined:

1) precleaning handling

2) cleaning chemistry/concentration

3) time

4) temperature

5) type of agitation

6) rinsing conditions

7) drying conditions

8) postcleaning handling

Where cleaning solutions are re-used in baths or sumps, the control parameters and equipment used should be defined (such as conductivity or pH) the limits should be defined, the person responsible for monitoring the baths should be defined, the type of report or logbook entry should be defined, the trigger points and alert levels should be defined, actions taken in response to these levels and finally the conditions under which the bath is dumped should be defined.



Alconox cleaners are available globally with consistent formulations and are GMP compliant. Downloadable certificates of analysis, technical bulletins, MSDS, trace analysis, and inhibitory residue testing are available from the Alconox website at www.alconox.com