If you suspect that your MicroBlaster is contaminated with oil, there are a few signs you can look for to confirm this.
The air lines that run clean air through a Comco MicroBlaster are a milky-white color when new. Exposure to oil causes these air lines to turn orange or yellow color. Take a look at the air lines compared to the right.
Oil has a tendency to pool in the regulator assembly of a Comco micro-abrasive blaster. Unscrew the black plastic bonnet to see traces of oil inside the regulator. Use the images below to compare against your own blaster interior. (Note: This can be a difficult area to access.)
When oil contamination becomes severe, abrasive media adheres to the filter element. If you suspect severe oil contamination, open the assembly to expose the filter element and look for large clumps of abrasive. The image to the left show abrasive clumping due to oil contamination.
While oil contamination can cause a major disaster inside your blaster, it is one of the easiest problems to avoid. The compressed air line running to a Comco MicroBlaster should pass through an oil filter and air dryer just before it reaches the unit. Not only does the oil filter protect the blaster components, but it also keeps oil from coating the desiccant or membrane filter inside the air dryer, prolonging its useful life.
The post Oil Contamination: The preventative measures you need to take appeared first on Comco Inc.
The Grip Wrist is the latest blast head designed for automated MicroBlasting systems. Unlike prior blast heads, it moves the part to the nozzle. See it in action and learn more. Continue reading
The post New Grip Wrist for JetCenter Improves Batch Processing appeared first on Comco Inc.
The Grip Wrist (pictured above) is the latest blast head created for our JetCenter Automated MicroBlasting System. You may have seen other blast head options including the Spin Wrist and the Twist Wrist. While each performs distinctively, all move the nozzle to and around the targeted part.
Take a look at this quick video to better understand its capabilities.
In the interview below, we dig into the design and capabilities of this new blast-head with Chief Engineer, Mickey Reilly.
[Reilley] The JetCenter, our latest automated system, features a very large travel envelope because it was initially designed to process 300 mm silicon wafers. Once we had that space, we wondered what else we could do with it. We thought, “what if we use that travel and space to load in a tray of parts, and then pluck each individual part and move it to the nozzle for blasting?” So we developed the Grip Wrist.
[Reilley] The Grip Wrist is a modification of our Gripper Spindle, which is a modification of our Vacuum Spindle. It has been a constant evolution for 15 years.
Chief Engineer, Mickey Reilley
Beveler with Vacuum Spindle, 1970s
Vacuum Spindle in Lathe
Gripper Spindle in Advanced Lathe
Grip Wrist in JetCenter
The 1st generation Vacuum Spindle was developed from the 1970s “spindle station” machine that looked like a record player. It’s so old that we don’t even have CAD models. This spindle had small bearings and a plastic o-ring rotary vacuum union. This design was used in our original Standard Lathe.
Significant design changes were made between the 1st and 6th generations, but the primary change to note is that the Gripper Spindle required a better seal to transfer air pressure to the spinning shaft. The original seals were only being used at vacuum (-14 psi), but the Gripper Spindle required high pressure (100 psi). So, the original seals weren’t going to cut it.
The new seals are a special Teflon material and ride against a hardened/ground/polished steel shaft. There are two sealing lips on each seal for better sealing and longer life. And these seals are capable of 100 psi. This spindle has new bearings, a new housing, new motor, new everything. We liked this new seal so much that we now use it on all of our spindles.
The Grip Wrist uses a custom-made PTFE double-lip seal against a hardened ground shaft. I tested the new seal to 100 million revolutions, and it still performed better than the old-style seal.
[Reilley] The Grip Wrist sits out of the way and above the blast stream. It operates in a downflow environment. It is completely sealed, including the spinning gripper. Even if powder manages to get past the seals, the internal components are also sealed. This approach to protection has proven its reliability in the field.
[Reilley] The Grip Wrist suits many applications we traditionally do in our lathes, but it enables batch processing. Spinal implants, dental implants, and bone screws are the most obvious candidates, but the possibilities are great.
The Grip Wrist is ideal for processing bone screws, dental implants, and more.
The post New Grip Wrist for JetCenter Improves Batch Processing appeared first on Comco Inc.
then on Comco Inc
Our offices will close from December 24th, 2020 to January 3rd, 2021. We will re-open on January 4th, 2021. However, the last day to place orders for consumables will be Friday, December 18th. Orders placed after that date will be filled in the new year.
PowderGate parts diagram
Make sure your Comco blaster is ON but not blasting (footswitch is not pressed). Put your finger over the opening of the nozzle for a few seconds, then release it. If you feel or hear a burst of air exit the nozzle, that indicates a leaky nosepiece. Replace it immediately. The nosepiece is easily accessible from the side of the AccuFlo® without having to remove the cover of the unit. Contact Technical Support at email@example.com or 1-800-796-6626 if you have any questions about wear and replacement.
When a modulator is too worn to seal properly, the abrasive stream starts off strong but drops off to almost nothing within 3-5 seconds.
In the MicroBlaster, a good modulator hums, and a worn modulator rattles.
This is the most accurate way to manage modulator maintenance. The AccuFlo modulator has a lifespan of 5,000 blast hours; whereas, the modulator on the MicroBlaster, Powerflo® and DirectFlo last about 2,000 blast hours.
*Housing assembly only; reuses the coil from existing modulator
HEPA filtration removes 99.97% of particles from the work chamber in the ProCenter Plus workstation. When the mallets can no longer knock spent abrasive from the filter surface, then the HEPA filter is full and needs to be replaced. HEPA filters tend to reach capacity after 6-9 months of regular use.
If your blasting system runs all day and/or processes a high volume of parts, then replace the HEPA filter after 3 months of use. If you are blasting with abrasive that is smaller than 25-microns in size or if you are blasting with sodium bicarbonate, then you should also replace the filter after 3 months of use. Sodium bicarbonate breaks down into dust after blasting, and those extremely fine particles embed deep into filter pores.
The post Annual Maintenance Reminder! appeared first on Comco Inc.
MicroBlasting is an excellent choice when cutting and etching brittle material because it’s a quick process. Nearly all of the deposited abrasive energy goes into breaking the material bonds holding the surface together.
MicroBlasting works well with ductile materials too, though the process can be slower than brittle parts with similar hardness. The resulting finish on a ductile material is rougher than on a brittle material because the impact of the abrasive causes the edges of each surface crater to smoosh upward.
MicroBlasting is so controllable, you can etch features with varying depths and sharp walls – but maintaining accurate measurements are crucial to achieving these results. There are a few ways to make these measurements:
Measuring via weight loss can be done in one of two ways. The first method is to weigh the part to determine how much material has been eroded. This method is great if the part is small and will not use much abrasive. The second is to weigh the blaster to measure how much abrasive has been spent. This method is better if a lot of abrasive will be used. Hydrodynamic seals are processed in this manner.
You can figure out the amount of time it takes to etch a specific material to your specifications pretty easily. First, experiment with different blast durations and measure the resultant depths. Then continue to experiment until you find the required duration. Just remember to keep your abrasive type, velocity, and quantity consistent, as these factors can also affect the depth of your cut (we’ll talk more about these later on). This method works best for very consistent parts, like wafers and surfaces for microfluidics.
Using separate measurement tools works especially well for depth control when creating pockets or trenches in a part. Some examples of processes we have used are listed below:
|MICROMETER||STYLUS PROFILOMETER||LASER TRIANGULATION||MICROSCOPE AND INTERFEROMETER|
|Tools We Use||Mitutoyo|| |
Mitutoyo SJ-201 with Surfpak-SJ software
(2um tip radius with 0.75 mN downforce)
Keyence LK-H008W sensor and LK-G5001 controller
(20um x 550um beam spot size)
Keyence VK-9700 and Zygo NewView 7000 series
(5x and 50x lens)
|Resolution||10 nm||5 nm||.1 nm|
|Real-World Depth Measurement||1000 nm||1000 nm||100 nm||1000 nm|
$2500 for profilometer
$2500 for software
$7000 for sensor
$3000 for controller
|Typical system cost aprox. $100,000|
As mentioned above, three abrasive factors determine how a material erodes when blasted. Finding the best combinations for your application (and keeping them consistent) is critical to repeatable results.
Typical particle velocities during controlled erosion applications are 150-225 m/s (492-739 ft/s), based on air pressure, nozzle geometry, and blast distance from the nozzle to the part. Velocity is controlled by the nozzle size, blast pressure, and distance from the nozzle to target. The simplest way to speed up your process is to dial up the pressure, but that could result in less precise depth control, leading to unevenness in the final surface. Worse, if you are using a mask, you could potentially destroy it before the process is complete.
Most applications benefit from the combination of a rich abrasive stream and fast nozzle speed with multiple passes
MicroBlasting usually takes 20-60 seconds per square inch of material blasted per pass. Most applications benefit from running the nozzle as fast as possible. Doing so prevents damage to masking material and provides better depth control per pass. Cutting deep channels or holes benefits from a leaner abrasive stream. Too much spent abrasive in the hole prevents new cutting action. When cutting or etching a part, less is more!
One of the most common abrasives used in cutting and etching applications is aluminum oxide. Being only slightly softer than diamond it cuts effectively for both brittle and ductile substrates. For very soft materials, like polymers, sodium bicarbonate is a better choice. It is able to transfer more cutting energy into the substrate.
The size of the particles is also important. The advantage of using a larger abrasive is an increase in material removal rates. The disadvantage is that it provides less depth control, increased surface roughness, and a less distinct transition at the edge of the blasted area.
The most common abrasive we use for etching ceramic wafers is 17.5 micron aluminum oxide. The finished RA is 0.15-0.3µ (or 5.9-11.8µin).
Most cutting and etching applications use a mask, but sometimes a part can be directly machined. Knowing when you need to use a mask and when you can go without one is crucial.
Direct machining is best when removing large, simple sections of material. A small nozzle and accurate parts-handling capabilities work together to cut a pattern into the substrate. The focused abrasive stream prevents overspray, eliminating the need for a mask, and reducing abrasive consumption.
Masked machining works well with applications that have many small features. To cut or etch a part using a mask, use a metal or polymer photo-resist material to expose only the areas that require blasting. Then, sweep the nozzle back and forth over the entire mask to erode fine layers of the exposed surface.
Consistent results require consistent blasting processes. While manual systems work fine for applications with low volume or less rigid tolerances, automated systems perform the vast majority of cutting and etching applications. For example, to create end effectors in semiconductor parts, small dots are masked while the rest is eroded away, leaving pillars. Creating features this precise are only possible through automation. By automating the parts-handling component of the blasting system, tight tolerances can be achieved—in some applications, as tight as 0.5µ.
Whether you are using an automated or manual system, the most important way to achieve repeatable results is by keeping all your variables constant. We look forward to helping you determine the best MicroBlasting system for your application!