Where are you located?

WA, USA

 

WA, USA

Well... you're trying to save on an investment of around $40K, considering your salaries up there, and if you do things right the first time, you might as well save up to 40% of that quantity by making your own, accounting for your time, the time taken by the guys you mentioned at CNC, parts and design... it's not bad if you also consider that you will end up owning a valuable piece of intellectual property.
Right now this is my main piece of advice: Avoid using a 24-bit ADC if you can, since they're far more complicated to use than a 16-bit one, are difficult to implement and require extensive programming. This can be easily seen by comparing the ADS1242's datasheet vs the one I'm suggesting. In both chips you're going to have to make multiple readings and average them for a reliable result, so speed won't be an issue.

 

I'm late to the party but I find it hard to believe the right choice here is to make versus buy. There is an industry built around filling. Surely there is something out there that could handle this job.

I would also worry about regulatory issues of using a DIY filler. If I was an FDA inspector, that would get my spidey senses tingling.

 

I'm late to the party but I find it hard to believe the right choice here is to make versus buy. There is an industry built around filling. Surely there is something out there that could handle this job.

I would also worry about regulatory issues of using a DIY filler. If I was an FDA inspector, that would get my spidey senses tingling.

I guess it all would depend on what the regulations in WA state are... and if they need to certify the weight scale and/or the dispensing unit.
I've been designing dispensers for almost two decades, and so far what he's mentioned is not that hard. Although I admit that it will be quite laborious.

 

I guess my point is, what is the acceptable failure rate, 1 in 10^6 ? 10^8? Even with a working system, it'll be hard to "prove" the reliability rate. A reputable and approved manufacturer may not accept liability, but when you use on-the-market, "state-of-the-art" equipment, that seems far less risky and easier to defend in a suit if such a thing ever happened.

Maybe I'm making a mountain out of a mole hill, but if you're in the business of putting mercury in peoples' mouths, precision matters.

 

Guess if a lot of capsules are made something mechanical, like a plate with 100 groves, powder from above then scraped off, then sucked out of each grove with a pump.

You could almost 3D print that of course accuracy wont be so great.

Filling the capsules slowly and checking the weight many times, not sure about that.

Probably the weight is checked one time after filling, discarded if it is off.

 

Probably the weight is checked one time after filling, discarded if it is off.

Fill by machine setting, verify by scale. That makes sense and actually adds a layer of verification.

 

I'm just sitting back looking puzzled. I have seen dentists assistants make amalgam fillings for 50 years, and they don't seem to be all that difficult. Lately, the preferred substance is UV cured white stuff. So, why reinvent a machine to make things that are already obsolete? Buy one cheap from a corporation that had to discontinue packaging mercury amalgam because less and less of it is being used.

 

Sooo.... you're not going to help me with my buggy-whip winding machine?

 

I'm just sitting back looking puzzled. I have seen dentists assistants make amalgam fillings for 50 years, and they don't seem to be all that difficult. Lately, the preferred substance is UV cured white stuff. So, why reinvent a machine to make things that are already obsolete? Buy one cheap from a corporation that had to discontinue packaging mercury amalgam because less and less of it is being used.

The OP's system seems to be self-contained capsule that can be crushed to bring the silver powder in contact with the liquid mercury - and no Hg exposure for the dental assistant. Hg vapor is a bit no, no.

Also a big bad issue will be improper alloy (amalgam) ratios. Too little silver and mercury suddenly extracts much more easily from the mixture.

This is a medical device. It will need FDA approval. Not going to be easy in a DIY setting. FDA asks: "...and who was the lead engineer on this project?" OP responds: "some guy online called #12, and another guy known as cMatinez"

 

Sooo.... you're not going to help me with my buggy-whip winding machine?

I just found out that there is still a specific US Patent classification for horse-whips. I never understood why all these innovation gurus talk about "buggy whips". If they had any real skills and had ever solved a customer's problem, these gurus would understand that a buggy doesn't go faster when whipped so that was a doomed product from the beginning. Horses go faster when whipped.

 

Thanks for the LOLs. I feel much more relaxed now, than when I think about the Hazmat team that is looking for me with intent to remove my fillings.

 

I'm late to the party but I find it hard to believe the right choice here is to make versus buy. There is an industry built around filling. Surely there is something out there that could handle this job.

I would also worry about regulatory issues of using a DIY filler. If I was an FDA inspector, that would get my spidey senses tingling.

I tried to locate one suiting this particular need, but couldn't ... If any such choice is available, ofcourse that would be the most feasible choice.

Maybe I'm making a mountain out of a mole hill, but if you're in the business of putting mercury in peoples' mouths, precision matters.

Mercury dispensing is the easy thing, it can be done very accurately using volume, and there are a lot of mercury dispensers around. Its the powder which is the problem.

 

I tried to locate one suiting this particular need, but couldn't ... If any such choice is available, ofcourse that would be the most feasible choice.



Mercury dispensing is the easy thing, it can be done very accurately using volume, and there are a lot of mercury dispensers around. Its the powder which is the problem.

Could the powder be converted into a gel (with a few additives) before dispensing? ... That way you could calculate quantity by volume instead of weight ... It's just an idea ...

 

Small volumes of powders are normally dispensed by dies. For example, a hole is drilled into a plate of steel. The hole diameter and plate thickness are calculated to be just the volume of power that meets your weight. The plate is set in a channel on a thicker steel table - the channel matches the length and width of the drilled steel plate. A plow wipes powder over the hole (without compressing the powder). The steel plate is pulled forward in the channel to align with a hole drilled into the channel. Powder drops through.

The powdered metallurgy industry has all kinds of presses, dosing and mixing equipment. Depending on the partial size of your alloy powder, a silver-tin alloy should become semi-structural with compression alone. At 80 to 90% theoretical density, pores should be accessible by mercury AND the alloy compaction would we friable and easily disperse as you start triturating with mercury.

On the other hand, there are powder dispensing machines with high accuracy, full mass documentation and already used in FDA approved applications... Unfortunately, production rate is about 1/50 of what a powder metallurgy press can do.

See
http://www.weighfill.com/powder-dispensing.html


For powder metallurgy presses...
Cincinnati Incorporated

Click here for company profilePO Box 11111
Cincinnati, OH 45211-0111
Telephone: 513-367- 7100
Fax: 513-367-7552

Dorst America, Inc.

Click here for company profile64 South Commerce Way
Bethlehem, PA 18017
Telephone: 610-317-2000
Fax: 610-317-6416

Gasbarre Press Division

Click here for company profileGasbarre Products, Inc.
590 Division Street
DuBois, PA 15801
Telephone: 814-371-3015
Fax: 814-371-6387

Lauffer Pressen

Click here for company profileMaschinenfabrik Lauffer GmbH & Co. KG
Industriestrasse 101
D-72160 Horb am Neckar
Germany
Telephone: 49-7451-9020
Fax: 49-7452-902100

Osterwalder Inc.

Click here for company profile1578 State Route 903, Suite #4
Jim Thorpe, PA 18229
Telephone: 570-325-2500
Fax: 570-325-2551

PTX - Pentronix, Inc.

Click here for company profileA subsidiary of Gasbarre Products, Inc.
41160 Joy Road
Plymouth, MI 48170
Telephone: 734-667-2897
Fax: 734-667-4350

SMS Meer GmbH

Click here for company profileMr. Norbert Nies
General Sales Manager Powder Presses
Ohlerkirchweg 66 - Postfach 100645
Moenchengladbach, Germany 41006
Telephone: 49-2161-350 1537
Fax: 49-2161-350 1859
UTRON Kinetics, LLC

Click here for company profile

 

Small volumes of powders are normally dispensed by dies. For example, a hole is drilled into a plate of steel. The hole diameter and plate thickness are calculated to be just the volume of power that meets your weight. The plate is set in a channel on a thicker steel table - the channel matches the length and width of the drilled steel plate. A plow wipes powder over the hole (without compressing the powder). The steel plate is pulled forward in the channel to align with a hole drilled into the channel. Powder drops through.

The powdered metallurgy industry has all kinds of presses, dosing and mixing equipment. Depending on the partial size of your alloy powder, a silver-tin alloy should become semi-structural with compression alone. At 80 to 90% theoretical density, pores should be accessible by mercury AND the alloy compaction would we friable and easily disperse as you start triturating with mercury.

On the other hand, there are powder dispensing machines with high accuracy, full mass documentation and already used in FDA approved applications... Unfortunately, production rate is about 1/50 of what a powder metallurgy press can do.

See
http://www.weighfill.com/powder-dispensing.html

Thanks a lot Gopher .. This is what my initial design was ... using volume for measuring powder weight, using drilled plates with appropriate volume holes .. I am just not sure which degree of accuracy we can achieve with using volume for powder quantity ..

 

Thanks a lot Gopher .. This is what my initial design was ... using volume for measuring powder weight, using drilled plates with appropriate volume holes .. I am just not sure which degree of accuracy we can achieve with using volume for powder quantity ..

Drilled holes in steel plates is how most medication tablets are made. They use statistical quality control. The unit I saw had 100 holes around the perimeter of a steel disk. It was rotating very fast and they would take the 1001st pill for weighing and quality control of a single pill and they would weigh the 1000 for overall quality check.

 

Drilled holes in steel plates is how most medication tablets are made. They use statistical quality control. The unit I saw had 100 holes around the perimeter of a steel disk. It was rotating very fast and they would take the 1001st pill for weighing and quality control of a single pill and they would weigh the 1000 for overall quality check.

So the question here would be if that technology is capable of delivering the 1% accuracy required for this application... I guess the critical factor would be the powder's density and how to keep it from either compacting or airing it too much so as to be within tolerance...

 

Maybe vibration. That would pack the powder equally per hole?

 

Maybe vibration. That would pack the powder equally per hole?

Yeap... vibration might be the key, The three critical factors would be amplitude, frequency and processing time. Assuming that humidity is not an issue...