The branding industry has made waves lately with the help of specialized part marking systems that offer amazing and attractive, cuts and designs to make your brand identifiable. Marking metal parts with stains or colored inks is a quick and easy way to make similar-looking parts or objects separately identifiable, indicate a fail-pass status, or simply confirm that a particular process has been executed, or completed.
Manufacturers from different industries make parts for a number of reasons: to distinguish between same-looking parts; mostly to indicate that a quality control check has been completed or a specific operational process has ended; to facilitate with the assembly; or link a component or product to a machine or assembly line where it was produced. Some parts such as calibration screws may also be marked with colored stains that become visible only under the ultraviolet light so to indicate whether the parts have been fiddled with or not.
A major common use of part marking systems for color marking is to distinguish easily between machine parts or other objects that look similar in structure, size or design. Although such parts or objects may be carved with letters, numbers or a totally different identifier, some companies stand out by making the decision to color code the parts as well, to simply and speed up the identification process on the wholesale or retail grounds.
For example, two rods may look similar and cylindrical in shape, but their function may be very different. Marking each part with a dissimilar color stripe is unarguably the easiest way to tell the parts apart.
One other major use of part marking systems is in the quality control department. Parts are generally marked after they have been passed through a quality control test to make sure whether they have failed or passed. Parts are marked to identify that particular processes have been completed. This is useful when the processes do not change the parts visibly.
Part marking systems are usually integrated into production or testing fixtures. One example can be a flywheel that is mounted on an engine using multiple bolts, which are then tightened simultaneously. When bolts of all parts have been torqued to requirement, the marking machine takes the position and applies a small, carved dot to ensure that the specific operation was executed and completed correctly. If somehow the dot is not present on the part, the operators downstream will know immediately that corrective action or additional inspection is required.
Parts are marked with different colors to facilitate assembly processes too. For instance, assemblers may put a stain dot on the brake calipers to ratify that the brake pads have been successfully installed before mounting the tires and the rims. Or, a similar situation in which a shaft is marked to identify which end to push in.
Marking from part marking systems is also used in stamping and other automotive processes to check contours of the stamped parts during the set-up process to indicate whether a crease is straight or a bend is angled to the correct radius. In these sort of applications, color marking gives an easy way to indicate any discrepancies so the machine operator can finely tune the setup process.
3 Major Marking Methods:
The most common part marking techniques include:
- Actuated Markers (with Handheld Valve)
- Contact Marking Systems (Pressing a pad, that is stain-saturated, against the part)
- Non-Contact Marking Systems (Spray Marking Systems)
Actuated Markers (with Handheld Valve)
These are one of the simplest part marking systems. These systems are used in processes like filling fluid in an automated transmission, and then marking its dipstick for visual validation.
Contact Marking Systems(Pressing a pad, that is stain-saturated, against the part)
These consist of a reservoir of stain or ink fitted with a dauber or pad and mounted on a cylindrical device like an air cylinder. As the parts move closer to their position, or as the process or tests are completed, the actuator proceeds to press the soaked dauber touching the part. The machine parts, after being marked, may need to be cleaned and dried to gain a satisfactory mark, depending on the fluid used in marking.
Non-Contact Marking Systems (Spray Marking Systems)
These part marking systems generally use an air-filled spray valve to apply stripes, bands and spots, using stain supplied from a disposable reservoir or a tank. Depending on its application, the valve can be attached to the actuator that moves the whole system to the part, or the valve can also be mounted on a fixed spot. In a few processes, the part is revolved while the valve puts a band of color on the external circumference.
Pigment & Maintenance:
Marking fluids, often called staining colors, paints or inks usually fall into two categories. They are either opaque or transparent.
Transparent color inks have higher viscosity than opaque colors do, therefore they dry slightly faster. They are generally used in making applications that have high tolerances like engine rods, or on light colored substrates. Transparent inks do not separate or settle.
Opaque inks use more quantity of pigment to produce a heavy mark. They perform well on dark and light colored substrates. These inks apply a bit thicker than the transparent inks, and therefore take a bit longer to dry. Thinner can be added to adjust the thickness. Because opaque inks have more pigment, they will settle after long time and the daubers will have to be agitated periodically for this to work correctly. Opaque inks increase the probability of clogging of spray nozzles, therefore they will require regular maintenance.
Nozzle clogging is one the common problems with these air-filled valves, especially when severely pigmented opaque stains and paints are used. To avoid the application of thick and heavy spray that will take longer to dry, valve stroke is generally reduced to “choke down”, i.e. the aperture to reduce the coating thickness. This ultimately causes the pigment to filter at the nozzle, leading it to clog.
Blockage can be reduced using low pressure, low volume (LVLP) spray method to apply ink. Because LVLP is suited to work with flow rates and lower pressures than the standard systems, longer valve strokes can be used. It leaves greater space around the needle, reducing the probability of pigment build-up to a point where it blocks the nozzle of the valve.
Separation is one other issue with the pigmented inks. It occurs when pigments separate from carrier and settle at the bottom of reservoir, which results in less consistent and fainter marks. These marks may not be identified by graphical scanning systems.
Both the issues i.e. separation and clogging can be prevented with LVLP spray part marking systems with a recirculating pump and a double-ported fluid head that will keep the fluid moving, so pigment remains in delay.
HeatSign’s new, recirculating spray – part marking system is the latest technology in part marking systems. A motor powered gear pump pulls the marking fluid from tank and supplies to spray valve. Here it enters from one side and exits from the other. After the fluid is returned to reservoir, slight agitation is produced that keeps the colored pigment from resting at the base of the reservoir tank. As 1 psi is enough pressure to keep the fluid in constant circulation, a long valve blow can maintain the free space around the needle, while a computer-controlled air delay after every shot reduces risk of clogging and keeps the nozzle clean.
How to Choose One from A Variety of Part Marking Systems?
When comparing non-contact and contact part marking systems, engineers must consider the following factors:
- Cost of marking fluid and the need to maintain stock (Cheap bulk bottles versus individual stain applicators and bottles)
- Marking Speed
- The time needed for replacing ink bottles or to refill a reservoir tank, and whether a system shutdown is required.
- The need for regular monitoring of the system to make sure that ink is filled in the bottle versus a tank filled once at the beginning of the shift.
- Cost and time of replacing dried out or contaminated daubers and pads.
After the downtime, line speeds, fluid costs and maintenance requirements are considered carefully, a non-contact spray – part marking system proves to be the most economical and long term choice.
If you want to learn more regarding the latest part marking systems, please contact us at HeatSign. We are a reputed seller of a variety of part marking systems. To get the best deals in the market, visit the website, www.heatsign.com. You can also email us on info@heatsign.com or call us on +86 15061477073.
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