How to Detect Stuck Bullets in Rotating Lead Casting Molds Using Sensors?

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How can I detect whether a rotating lead-casting mold has actually emptied after the bullet is released?

Use a sensor just past the mold exit to verify that the bullet really left the cavity; an optical or mechanical sensor can detect the slug’s exit, and the machine should only continue if that sensor is triggered, otherwise stop and alarm the operator [#21661531] If you want extra protection, fit both an exit-detection sensor and a second sensor that checks for a still-occupied mold, so the system can retry or stop safely [#21661531] For a hot, lead-contaminated environment, fiber-optic sensors with glass leads were suggested as a suitable high-temperature option, and capacitive sensors were also mentioned as alternatives [#21661539] Another idea was to add a diverter/flap in the product path and use weight/resistance timing so the machine pauses if the expected mass is not present [#21661536]

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Suggesting sensor checks for stuck bullets in molds
#1 21661530 20 Mar 2012 20:02

Dimitar Bo Dimitar Bo

Anonymous
Suggesting sensor checks for stuck bullets in molds
Post #1 21661530 20 Mar 2012 20:02

I am trying to come up with a way to check if a casting mold has emptied after casting.
It is for a lead casting machine, that pours molten lead into multiple molds. The molds rotate and after the lead solidify they open and drop the bullets down, then they close and repeat the process. The thing is that sometime bullets will stay stuck in the mold and that will cause molten lead to spill down, creating all kinds of problems.
The molds have two holes, that vary in diameter depending on the caliber - 9mm, 10mm, .45. The molds are hot after the lead is poured. Although the molds are made of iron, they are sensitive to physical damage - any burs that are created will hang the bullets.
This is a picture of the machine and the molds.

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Dual sensor scheme to detect stuck bullets
#2 21661531 20 Mar 2012 21:59

Frank Bushnell Frank Bushnell

Anonymous

Dual sensor scheme to detect stuck bullets
Post #2 21661531 20 Mar 2012 21:59

Just a quick thought:

A light and optical sensor mounted just past the exit point detects the reflection of a still occupied space (because the new casting is shiny), pauses the machine, moves it back and wallops the mould with a hammer (OK, weighted linear actuator) to free and drop the slug.
It restarts.
If the mould is then still occupied, it stops the machine and sounds an alarm to call the operator.
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Update: After reading Tony Matteo's comment below, an alternative is to detect the exit of the bullet from the mould by an optical or mechanical sensor, then have the machine continue only if that sensor is activated.
If not, it will stop and activate the operator attention signal.

(For absolute safety, you could fit both sensors to the control system at minimal additional cost.)
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Graphite powder spray to prevent mold seizing
#3 21661532 20 Mar 2012 23:35

Jonny Death Jonny Death

Anonymous

Graphite powder spray to prevent mold seizing
Post #3 21661532 20 Mar 2012 23:35

Might seem like more trouble than it's worth but incorporating an automated sprayer that spits out a puff of graphite powder, or something similar, into each mold after each casting would probably eliminate the burring and seizing issues. Graphite might not be the exact right compound but I strongly believe adding such a component to the overall mechanism will get it to work without further issue. .
#4 21661533 21 Mar 2012 02:40

Dimitar Bo Dimitar Bo

Anonymous

Post #4
21661533 21 Mar 2012 02:40

It is worth a try.
I've never used them, can you recommend something?
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#5 21661534 21 Mar 2012 02:44

Dimitar Bo Dimitar Bo

Anonymous

Post #5
21661534 21 Mar 2012 02:44

The thing with spraying or applying any type of coating too often is that eventually it will build up on the walls, decreasing the diameter of the bullets. Also any liquid left in the mold when the molten lead is poured will result in an explosion caused by the steam, the so called "tinsel fairy visit" as its known among lead casters.
#6 21661535 21 Mar 2012 06:26

Jonny Death Jonny Death

Anonymous

Post #6
21661535 21 Mar 2012 06:26

The graphite will adhere to the bullets and make them shoot much much better, You must be unfamiliar with graphite, it's not a liquid though some companies blend it with oils and sell spray graphite.

An example of graphite is what everyone calls "lead" in pencils.
Trust me, it will work and improve the bullets performance as well.
Weight-triggered diverter and mold inspection questions
#7 21661536 21 Mar 2012 08:04

Tony Matteo Tony Matteo

Anonymous

Weight-triggered diverter and mold inspection questions
Post #7 21661536 21 Mar 2012 08:04

Mr. Bushnell
Pretty much answered your request (checking casting mold contents )

Also as the product is going down the shoot after mold releases, a diverter / resistance (flap/panel/wheel) in synchronys timing of operation allowing to release by weight > when weight is not grater than X mold will pause - alarm waiting for attention with out urgency.

However A few questions may lead to eliminate this glitch, Is this random or specific mold,molds. How offend occurrence, conditions, always been a problem, new, more frequent? Your referring to Iron molds sensitive to physical damage, any Burs that are created? will hang the product ! is that what is happening or just a condition you know of or has been suggested?

As the release goes please ( do-not ) use any release product not approved for this specify problem.
With out first identifying the exact reason!
The mold s will benefit from being polished and harden with out changing dimensions. Professional harding & polishing as in racing part.

The manufacture may have a answer for you or want to sell you new molds

All The Best
#8 21661537 21 Mar 2012 08:34

Jonny Death Jonny Death

Anonymous

Post #8
21661537 21 Mar 2012 08:34

Trust me, graphite dust puffed into each mold before casting will save you the trouble of building a sensor system unless you really want to. Should also make the bullets shoot more accurately and faster.
#9 21661538 21 Mar 2012 17:11

Dimitar Bo Dimitar Bo

Anonymous

Post #9
21661538 21 Mar 2012 17:11

I have to find an electrician to try the optical sensor idea.
The manufacturer strongly warns against any burs on the mold, they recommend cleaning with toothbrush only.
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Fiber optic or capacitive sensors for mold detection
#10 21661539 01 Apr 2012 13:54

John King John King

Anonymous

Fiber optic or capacitive sensors for mold detection
Post #10 21661539 01 Apr 2012 13:54

I've used fiber optic sensors in similar applications in the past. I know high temperature solutions are available (Glass rather than plastic). Similar to the following:

http://www.automationdirect.com/adc/Overview/Catalog/Sensors_-z-_Encoders/Fiber_Optic_Sensors

I've used Keyence and Moeller Electric i in the past. One similar project we used a very small sensor to detect the existance and proper orientation of tiny plastic bushings.

*You could also look into capacitive sensors*
http://www.engineerlive.com/Electronics-Engin...sensors_feature_extended_sensing_range/21590/

It may be more resistant to lead contamination if you can find one with the right size and temperature rating.

There are many other possibilities.. Mold vibrator? Camera? Reed Swtich
#11 21661540 04 Apr 2012 15:56

Resis Tor Resis Tor

Anonymous

Post #11
21661540 04 Apr 2012 15:56

It sounds from what I've read here preventing the bullets from getting stuck in the first place is the answer. Although after that you can have a sensor that weights the bullets as they come out or optical sensor that counts them as they come out.
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Topic summary

The discussion addresses detecting stuck bullets in rotating lead casting molds that pour molten lead into multiple caliber-specific molds (9mm, 10mm, .45). The molds rotate, open, and drop bullets, but sometimes bullets remain stuck, causing molten lead spillage and operational issues. Proposed solutions include using optical or mechanical sensors positioned near the mold exit to detect the presence or absence of bullets by reflection or mechanical activation. If a bullet is detected as stuck, the machine can pause, attempt to dislodge the bullet via a mechanical actuator (e.g., a weighted linear actuator), and if unsuccessful, stop and alert the operator. Alternative detection methods suggested include capacitive sensors, fiber optic sensors rated for high temperatures, and weight-based detection systems. Preventative measures focus on reducing mold burring and sticking by applying graphite powder as a dry lubricant inside molds, which also improves bullet performance. However, caution is advised against liquid coatings due to buildup and steam explosion risks. Mold maintenance through careful cleaning and professional polishing is recommended to avoid burs that cause sticking. Brands mentioned for sensors include Keyence and Moeller Electric, with AutomationDirect cited as a supplier of fiber optic sensors. The discussion emphasizes combining sensor detection with mechanical clearing and preventive lubrication to ensure reliable mold emptying and casting quality.
AI summary based on the discussion. May contain errors.

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How to Detect Stuck Bullets in Rotating Lead Casting Molds Using Sensors?

How to Detect Stuck Bullets in Rotating Lead Casting Molds Using Sensors?

How can I detect whether a rotating lead-casting mold has actually emptied after the bullet is released?

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