Robotic abrasive blast cleaner

[rdixiemiller]

Comatose, not a bad idea...I was thinking Teflon or some other material that won't damage the threads....again, I could see the parts "lined up on a table" with this mount in place, ready to go....it would be pretty slick IMO

I would make the rods out of steel tube, use a draw rod and a urethane expanding plug to grip the threads. Depending on how many you do a week, it can be manually clamped or use an air cylinder.
How heavy it the part?

 

[Orange Vise]

I wouldn't use a 6-axis robot in this application. Not only is it overkill, there are intricacies to blasting that would make programming a real pain, e.g. missed spots.

Instead, I would have a simple turn table rotating the part, and a single-axis linear stage moving the blast nozzle in and out towards centerline. Think of it like a 1-axis lathe. The stage can be entirely outside of the blast cabinet. A rod bolts to the carriage and goes through the blast cabinet side with a replaceable hydraulic/pneumatic rod seal. Blast gun/nozzle mounts to the end of the rod.

I'd control it with two Clearpath MCPV servos and an Arduino. You're looking at $2-3K for the entire automation setup, and once you get it going, tweaking the program to get the best blast pattern would be quite simple. Alternatively, you could use something like LinuxCNC, Centroid, or Mach to control SDSK/SDHP servos with straight up G-code. This will give you more control over feeds/speeds, but your electronics cabinet will end up being a lot more complicated.

As for the flip, I'd do it manually. The arrangement described above is easy to isolate critical components from blast media. Exposed parts like the rod, seals, etc. are low cost consumables. Adding an automated flip complicates this quite a bit. If you have a big enough blast cabinet, you could hit Side A and Side B at the same time with two turn tables. This can give you a lot more unattended run time.

 

[john.k]

You can "bounce" blast media to do a rear surface without rotation.........those not familiar with abrasive blasting have a steep expensive learning curve of sudden seizures and destroyed equipment to negotiate .....I would definitely use impeller blast with a robot .....or have a dozen spare robots to use in rotation ......the most abrasion resistant surface is pure soft pink rubber..........the crowd I was working for replaced the old guys with qualified millenial engineers ,they spent fortunes on stuff like Belzona, 1/4 ton of Belzona disappeared in a week,where soft rubber lasted six months.

 

[neilho]

Tumbling has been casually dismissed, but my experience has been that tumblers are much gentler than blasters. Masking holds up better, too.

 

[M. Roberts]

Good morning all. The part weighs about 15#. Rdixie; I was contemplating that, but thought that was too many moving parts, thus being subject to the effects of the blast operation....in addition, I would think that the part would need to be "clocked" with a little more care.

neilho; the part is comprised of silicon carbide, and is 13.5" in diameter, the parts have residual silicon beads and other remnants from their time in a vacuum oven; not that I have experience with tumbling, I just don't see it working. Blasting works well, just with all involved, it is inconsistent with all involved.

Orange vise: I think that I understand your thoughts; do you have drawings and/or know someone that has build anything similar? I'm open to ideas.

 

[M. Roberts]

John K.; do you have a trade name for the rubber you are talking about? or a source?

 

[neilho]

Ah, was wondering about the material. My experience is primarily with tumbling aluminum, so I'll plead ignorance on this one.

Most tumbling shops/suppliers/manufacturers (often the same) will gladly do a free analysis, tumble a sample and recommend a process in hopes of supplying the consumables and equipment or doing the work. If there's someone near you, it might be worth a call, but on the other hand, maybe you've already done that.

neil

 

[register]

I was going to recommend a repurposed welding or painting robot, but 15# is on the upper end of the common payload range for those, let alone if you stick it out on an extension pole to get the last three joints out of the line of fire.

I would think about attaching the nozzle to your robot and designing a fixture that allows the robot to flip the part. Maybe something with a light spring load and a trigger that the end effector can actuate without it having the robot handle the part itself. The human operator could re-cock the fixture to the loaded position every time they exchange the part.

 

[M. Roberts]

Guys, this is getting more interesting. I found out this morning, that last year we had installed a blast room (16' x 10'?) to facilitate large parts...supposedly it isn't effective (another issue) and to use it, one needs to wear a protective suit...therefore, no one wants to use it, and it has become a storage unit...pretty pitiful...I can definitely see incorporating this in the automation scheme....I still would like to find someone knowledgeable of the robots in my area....

 

[M. Roberts]

Guys, Good morning. Still working out the details, but the attached pic shows what I have in mind.

Mark

 

[Strostkovy]

Guys, this is getting more interesting. I found out this morning, that last year we had installed a blast room (16' x 10'?) to facilitate large parts...supposedly it isn't effective (another issue) and to use it, one needs to wear a protective suit...therefore, no one wants to use it, and it has become a storage unit...pretty pitiful...I can definitely see incorporating this in the automation scheme....I still would like to find someone knowledgeable of the robots in my area....

I built a blast room like that. It takes a ton of care in the design of it to make it comfortable and worthwhile to use. It needs excellent ventilation for visibility, the breathing air needs to not be hot (the standard of using the compressor to provide breathing air is incredibly stupid. I use a regenerative blower to move fresh, cool air at as high of a volume as the operator desires. A comfortable helmet, a comfortable trigger, and comfortable hose routing is really important.

You can also save a ton of time by using the correct blast media for the job.

 

[Strostkovy]

I find neoprene to be a plenty durable rubber for blasting, and use it in replacement valves I made for our pressure pot.

Do not use silicone. Terrible for paint and powder coat.

 

[EmGo]

I built a blast room like that. It takes a ton of care in the design of it to make it comfortable and worthwhile to use. It needs excellent ventilation for visibility, the breathing air needs to not be hot (the standard of using the compressor to provide breathing air is incredibly stupid.

But a robot wouldn't care ...

 

[Strostkovy]

But a robot wouldn't care ...

Sure, but it's probably worth getting that blast room worth using, robot or not.

You aren't going to reteach the robot for every prototype or oddball part.

 

[john.k]

Intersting about the protective suit.......my old boss made his first millions by having a team of blasters working in an open yard ,zero protective bar a wet rag wrapped around the mouth......as the blast medium used was illmenite ,which is a heavy black sand ,the heat in the yard was like working in a furnace ....(not only is the sand jet black,but it is also somewhat reflective ,it sparkles in the blazing sun.)

 

[john.k]

A blast room using shot or grit is very expensive venture to set up......there needs to a shot recovery and recycling system and a dust collection system ,generally combined with the shot recovery........a couple of tons of shot will keep a big room going indefinitely....IF.... the blasters /laborers are careful about "carry out"........or you will find a ton of new shot every week being poured in to keep the process functioning.......then there is the maintenance .....everything to do with gritblasting is costly.

 

[Strostkovy]

A blast room using shot or grit is very expensive venture to set up......there needs to a shot recovery and recycling system and a dust collection system ,generally combined with the shot recovery........a couple of tons of shot will keep a big room going indefinitely....IF.... the blasters /laborers are careful about "carry out"........or you will find a ton of new shot every week being poured in to keep the process functioning.......then there is the maintenance .....everything to do with gritblasting is costly.

We go through 50 pounds of fine aluminum oxide per month. Most of it disappears as dust, and a small pile forms in front of the urinal.

We used to have to do major maintenance/repairs every week, but now we only do maintenance every three months and major component replacements every year. It took a lot of modifications to our equipment to get there.

 

[john.k]

Steel shot/grit doesnt degrade much mechanically........but,you have to be careful of atmospheric moisture .....the whole system can turn into rock overnight ....in some climatic conditions Ive heard of having to remove all the shot from the system every night...........this is one reason why 24hr operation is good ,two 10 hr shifts .

 

[M. Roberts]

Good morning. Thanks for the input. Part of the issue is that we already have the room, and it is literally used as a storage closet; nobody wants to use it because of the PPE requirements. I suggested making it into a "problem solving room", complete with two pair of boxing gloves; that suggestion wasn't heeded well . We are ramping up the production of one part; requiring 100+/- parts per week; average blast time 20 minutes each, that equates to 33-1/3 hours per week...I think that warrants a look at. Regarding the collection of the blast media, the system is modeled with the dust chute directly below the nozzle; I am hoping that this would catch the majority of the media...

 

[Nickraatz]

Good morning. I am looking for an automated/robotic abrasive blast system for the cleaning of 14" diameter x 5/8" thick parts. Here is the catch; because both faces needs to be blasted, I would like for the part to be attached to the robotic arm, so that it can be manipulated around a fixed nozzle(s). This would allow me to clean both faces without flipping it. The part has many holes with the possibility of mounting a fixture or mounting lug to to accommodate automatic loading and unloading, I see a lot of potential. I have done a few searches on the web without success; hopefully someone here has a simple solution.
Thanks, Mark

I know this doesnt help you, but we actually had a blast cabinet exactly as you described at a previous company I worked for. It was a fully automated finishing cell at an investment casting facility. Operator would place parts on a plate and when it was full it would advance down a conveyor. Once under a vision system a robot would pick the parts and place it on a grinding robot fixture which would grind the "gate" off. First robot would pick part back off grinding fixture and place part on a swing table. Door to blast cabinet would open and swing table then would swing in. Robot inside of cabinet would pick the part and then move it around the fixed nozzle and it would clear leftever ceramic from the various holes of the casting. When the part was done the door would reopen and robot would drop parts into a tote. Most of our automation was built in house, but I do know we consulted with various companies to get what we wanted. Sure was a lot of fun changing out the robot condoms inside of the grit blast cabinet.

One thing I do remember about the cabinets was using Goff AR plates to line the inside. Goff was the brand of shot blasters we used in every plant, I would bet that an engineer may have reached out to them on this project.