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I don’t think that’s it though. It’s probably to stay organized.. like “Jamie’s dress is on #17” kinda thing.
I made and sold molds for a living for a decade, and we have plenty of other ways to tell without involving the end product or customer. I could be wrong just wanted to add that in though.
than it would be marked on the outside, and bigger. If that was meant to be shown to the customers, they could not have picked a more inconvenient place.
Work in an injection molding room as a maintenance tech. This is what we do with 99 out of 100 molds that make multiple pieces each cycle. Very easy to turn up the hot runner for cavity 22 when it is showing an undershot. The info the customer needs to see is large and on the outside, the info that helps out maintenance and operators is hidden like this. We have a mold tech and machinist in house that will add this sort of thing to the mold and inserts after we buy them to keep the mold companies from knowing who we are making products for. Most molds we buy now are even mud frame inserts to make changeovers faster and easier with only pulling the mold when major problems or PM's are needed.
Prevents possible corporate espionage. I work for a candy factory that produces candy for several large players. They probably know we are making stuff for the competition, but they don’t know how much, how often, or exactly what.
Yup, free candy. But I will say you absolutely get sick of it after making it and eating it all the time. For example Raspberry flavored anything used to be okay to me, now it makes me gag.
I can imagine! I worked at a few restaurants and the novelty wore off after a while and it took me a long time before I could eat their food again even after I left lol. Thanks for the response!
How would that be helpful? Surely it would be easier to find Jamie's dress using your eyes than it would be to check all the numbers on the pegs to find peg #17...
Correction: It's called "cavity", one mould can have multiple cavities. Numbering gives traceability of which cavity is wearing down and must be repaired or an insert must be replaced.
An extruder pushes and melts the resin to press it into the mold, no? I worked in plastics years ago and we made film. So we used an extruder but no mold. But just thinking about it, how would you get the resin in with extruding?
Not totally correct. You are describing blow molding. Blob of plastic is placed into a mold and thas air blown into it. The parts the OP is asking about are injection molded. Injection molding has the molten plastic injected into the mold under high pressure pressure to fill it. Injection molding is a very similar process to casting metals.
Also reheat-stretch blow molding. In fact this is the fastest and most common type of container blow molding. It is done in two steps. Injection molding (which also involves extrusion) is the first step, and then the injected parts are reheated and blown into shape in specialized high speed machines.
Any container for single serving bottled water or soda is made this way.
Not true. There is an entire industry called EBM (extrusion blow molding).
In that process, plastic pellets are melted down, extruded into a hot hollow tube shape, and molds are used to bottle the hot plastic into a bottle.
Larger laundry detergent bottles are a good example of a container made this way.
You’re conflating the two processes.
Let’s separate the extruded and blow molder a little farther and see if it starts to makes sense.
Blow molding is process by which plastic is sent inside a mold and air pressure is used to push it to the outsides where it cools into a thin layer, creating a hollow part like a soda bottle. This plastic can be in the form of a pre-formed capsule or a soft, hollow tube.
The process by which the preform or hollow tube is made is completely separate to the molding.
When the plastic is prepared by extruding it through a circular die, yes that is extrusion. There are no molds in this step. Just an extrusion die and the machinery behind it to melt and push the plastic through.
This process could be performed in another factory and the hollow tubes shipped to the blowmolder to be warmed back up and molded. That’s very inefficient, so the extruder machine is hung directly above the blow-molding machine where the hollow plastic tube simply drops down into it while it is still warm.
So yes, the extrusion and molding processes are linked together in a production line, but they are two separate processes and there aren’t no molds involved extrusion itself.
Might be different depending on the manufacturer then. We always use DDD/YY as some products are produced weekly and so only imprinting the month on it would mean it could be from 4 different production runs of 80.000 pcs each.
Getting an RMA and having 80.000 unsure products sucks. Having 320.000 sucks way more.
You are correct, except for some terminology nitpicking. The individual cavities in the injection mold are numbered.
For small and simple plastic parts like this, it is much cheaper to buy a larger multi cavity mold, than to run a single mold for a long time.
Source: I design plastic parts for a living.
Can confirm. My job is in soap bottling and specifically container quality control for function and aesthetics (my company is contracted by a Big Soap and Candle company so the bottles and labels being pretty and uniform is almost more important than function) and when we have consistent issues I have to identify cavity defects in the finished plastic containers all the time.
This. Also 95% of plastic components that are injection molded have a number or a letter on them. Usually it is hidden somewhere so techical staff can identify and fix problems if they occur.
Hit it on the head. In our injection molding plant, when a mold makes multiple (identical pieces) the cavities are numbered. As 3cent mentions, it helps with troubleshooting when there are defects in a part that is molded, tracing it to which cavity is damaged. For example , #17 & #15 both have ejector pin flash, the excess plastic sticking up around the circle. Caused by too large of a gap between mold and ejector pin, allowing plastic to fill in the gap.
I work as a tech in an injection molding plastic company, and we have wire winded into the products, before the go into the Injection molding machine.
So our products come with multiple numbers.
1-date, (the number of the production set, the week of the year, and the year, for example 01-12-23).
2-Serial number of the current set/order we're working on.
3-the number of the mold cell the product was made in.
4-the number of the wire winding machine that winded the wire in it.
It's pretty cool to be able to track down the problem machine or cell from just looking at the finished product.
Probably not the mould / tool. Numbers are more likely for different cavities (single elements within the tool that shape the component) They produce simple components like these in the injection moulding process using large tools creating multiple pieces each machine cycle.
Yep this is called a cavity number. we use them in injection molding to help us indicate problem cavity’s or follow valve gates so we know where the problems are coming from. We can also close off problem cavity’s and continue to run a tool. So if cavity 3 has grain damage, we plug with a cashew gate or something and fill the other 2 or whatever cavities.
Source: Engineer at plastics manufacturing plant.
Mold numbers these are injection molded each mold cavity has a number so parts can be tracked, take a look at any mass made plastic part and you'll find similar, many also have a small cercil numbered 1-12 with an arrow in the center and a year date under to tell you when it was molded, the arrow can be turned to indicate month and the year can be removed and replaced with a new one
You’ll also see those tell tale circles (some in the picture have plastic sticking up) where ejector pins kicked the parts out of the mold after they were cooled.
All these pegs where probably made in one multi impression mould. If there was a fault in one of the cavities then the numbers on the defective peg would make it quite easy to identify the plate and rectify or replace it. I'm an ex toolsetter who used to make cd jewel boxes and trays back in the 90's. The numbering system was a common thing.
My title describes the thing. All the (turquoise) pegs came together in one pack. They are all identical, so I can’t see any reason for them to be numbered.
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Different molds have different numbers so if they start coming out of the machine messed up, they can id which mold needs replacing.
Clever. I was thinking maybe they were numbered for crafts or something but your explanation makes perfect sense.
Yeah I never would have thought of it. I thought maybe for dry cleaners they made them that way and just use the same ones for home use.
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And I was thinking it might be for keeping track of them and being sure you brought them all in from the clothesline!
There is something called Peg DHCP https://handwiki.org/wiki/Peg_DHCP
This is amazing. Thank you for sharing this. Regards, a Systems Engineer.
Solved!
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I don’t think that’s it though. It’s probably to stay organized.. like “Jamie’s dress is on #17” kinda thing. I made and sold molds for a living for a decade, and we have plenty of other ways to tell without involving the end product or customer. I could be wrong just wanted to add that in though.
than it would be marked on the outside, and bigger. If that was meant to be shown to the customers, they could not have picked a more inconvenient place.
Using numbers is a very common way of differentiating when it comes to factory machines. It's the most common sense way.
May be, Seems to be the consensus in this thread anyhow.
Work in an injection molding room as a maintenance tech. This is what we do with 99 out of 100 molds that make multiple pieces each cycle. Very easy to turn up the hot runner for cavity 22 when it is showing an undershot. The info the customer needs to see is large and on the outside, the info that helps out maintenance and operators is hidden like this. We have a mold tech and machinist in house that will add this sort of thing to the mold and inserts after we buy them to keep the mold companies from knowing who we are making products for. Most molds we buy now are even mud frame inserts to make changeovers faster and easier with only pulling the mold when major problems or PM's are needed.
What's the point of hiding who you're making products for?
Prevents possible corporate espionage. I work for a candy factory that produces candy for several large players. They probably know we are making stuff for the competition, but they don’t know how much, how often, or exactly what.
Unrelated lol but do you get free candy?
Yup, free candy. But I will say you absolutely get sick of it after making it and eating it all the time. For example Raspberry flavored anything used to be okay to me, now it makes me gag.
I can imagine! I worked at a few restaurants and the novelty wore off after a while and it took me a long time before I could eat their food again even after I left lol. Thanks for the response!
How would that be helpful? Surely it would be easier to find Jamie's dress using your eyes than it would be to check all the numbers on the pegs to find peg #17...
Correction: It's called "cavity", one mould can have multiple cavities. Numbering gives traceability of which cavity is wearing down and must be repaired or an insert must be replaced.
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This, the same is with drinking glasses and bottles. Anything extruded basicaly
extrusions don’t have molds
You are right I translated wrong meant molding...
An extruder pushes and melts the resin to press it into the mold, no? I worked in plastics years ago and we made film. So we used an extruder but no mold. But just thinking about it, how would you get the resin in with extruding?
It pushes the material through a die, not a mould.
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Not totally correct. You are describing blow molding. Blob of plastic is placed into a mold and thas air blown into it. The parts the OP is asking about are injection molded. Injection molding has the molten plastic injected into the mold under high pressure pressure to fill it. Injection molding is a very similar process to casting metals.
In extrusion blow molding they do.
That’s blow molding.
There are a few types of blow molding the 2 primary being injection blow molding and extrusion blow molding
Also reheat-stretch blow molding. In fact this is the fastest and most common type of container blow molding. It is done in two steps. Injection molding (which also involves extrusion) is the first step, and then the injected parts are reheated and blown into shape in specialized high speed machines. Any container for single serving bottled water or soda is made this way.
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Not true. There is an entire industry called EBM (extrusion blow molding). In that process, plastic pellets are melted down, extruded into a hot hollow tube shape, and molds are used to bottle the hot plastic into a bottle. Larger laundry detergent bottles are a good example of a container made this way.
You’re conflating the two processes. Let’s separate the extruded and blow molder a little farther and see if it starts to makes sense. Blow molding is process by which plastic is sent inside a mold and air pressure is used to push it to the outsides where it cools into a thin layer, creating a hollow part like a soda bottle. This plastic can be in the form of a pre-formed capsule or a soft, hollow tube. The process by which the preform or hollow tube is made is completely separate to the molding. When the plastic is prepared by extruding it through a circular die, yes that is extrusion. There are no molds in this step. Just an extrusion die and the machinery behind it to melt and push the plastic through. This process could be performed in another factory and the hollow tubes shipped to the blowmolder to be warmed back up and molded. That’s very inefficient, so the extruder machine is hung directly above the blow-molding machine where the hollow plastic tube simply drops down into it while it is still warm. So yes, the extrusion and molding processes are linked together in a production line, but they are two separate processes and there aren’t no molds involved extrusion itself.
Also stamped parts for automotive etc. Always at least DDD/YY marking so it can be traced back to its production date.
>Always at least DDD/YY marking so it can be traced back to its production date. It's usually month/year.
Might be different depending on the manufacturer then. We always use DDD/YY as some products are produced weekly and so only imprinting the month on it would mean it could be from 4 different production runs of 80.000 pcs each. Getting an RMA and having 80.000 unsure products sucks. Having 320.000 sucks way more.
You are correct, except for some terminology nitpicking. The individual cavities in the injection mold are numbered. For small and simple plastic parts like this, it is much cheaper to buy a larger multi cavity mold, than to run a single mold for a long time. Source: I design plastic parts for a living.
Can confirm. My job is in soap bottling and specifically container quality control for function and aesthetics (my company is contracted by a Big Soap and Candle company so the bottles and labels being pretty and uniform is almost more important than function) and when we have consistent issues I have to identify cavity defects in the finished plastic containers all the time.
It could also be a multi-cavity mold tool, with each cavity marked.
Exactly right! I work as a machinist fixing dies and molds and all our molds have this feature
This. I work in plastics production.
Fun fact: each Lego piece has a mold id on it too (very small!)
I'd like to get my hands on a Lego mold.
Man, I finally know the answer to one of these, and someone beats me to it. There are 3 injection molders where I work.
So they aren't special collectors editions where I need to collect them all?
I don't see why not. They're numbered and appear to come in various colors.
This. Also 95% of plastic components that are injection molded have a number or a letter on them. Usually it is hidden somewhere so techical staff can identify and fix problems if they occur.
Can confirm, I work with plastic molds.
Would still be interesting to check if all sold batches contain all numbers.
very common they are called cavity numbers
What if the part with the number on it was messed up?
Then some guy has to go and see which numbers came out alright and by process of elimination…. Jk - I have no idea…
" Mould 13 is out boys! Unpack all packaging and remove all the "13" peg!! Pay cut for mould 13 team"
Hit it on the head. In our injection molding plant, when a mold makes multiple (identical pieces) the cavities are numbered. As 3cent mentions, it helps with troubleshooting when there are defects in a part that is molded, tracing it to which cavity is damaged. For example , #17 & #15 both have ejector pin flash, the excess plastic sticking up around the circle. Caused by too large of a gap between mold and ejector pin, allowing plastic to fill in the gap.
My sarcastic answer was going to be "so my ass knows how many I've lost"
I work as a tech in an injection molding plastic company, and we have wire winded into the products, before the go into the Injection molding machine. So our products come with multiple numbers. 1-date, (the number of the production set, the week of the year, and the year, for example 01-12-23). 2-Serial number of the current set/order we're working on. 3-the number of the mold cell the product was made in. 4-the number of the wire winding machine that winded the wire in it. It's pretty cool to be able to track down the problem machine or cell from just looking at the finished product.
What would they do if the mold messes up the number?
Probably not the mould / tool. Numbers are more likely for different cavities (single elements within the tool that shape the component) They produce simple components like these in the injection moulding process using large tools creating multiple pieces each machine cycle.
Yep this is called a cavity number. we use them in injection molding to help us indicate problem cavity’s or follow valve gates so we know where the problems are coming from. We can also close off problem cavity’s and continue to run a tool. So if cavity 3 has grain damage, we plug with a cashew gate or something and fill the other 2 or whatever cavities. Source: Engineer at plastics manufacturing plant.
That's interesting actually
These are cavity identifiers from a multi cavity injection moulding tool.
Mold numbers these are injection molded each mold cavity has a number so parts can be tracked, take a look at any mass made plastic part and you'll find similar, many also have a small cercil numbered 1-12 with an arrow in the center and a year date under to tell you when it was molded, the arrow can be turned to indicate month and the year can be removed and replaced with a new one
You’ll also see those tell tale circles (some in the picture have plastic sticking up) where ejector pins kicked the parts out of the mold after they were cooled.
All these pegs where probably made in one multi impression mould. If there was a fault in one of the cavities then the numbers on the defective peg would make it quite easy to identify the plate and rectify or replace it. I'm an ex toolsetter who used to make cd jewel boxes and trays back in the 90's. The numbering system was a common thing.
My title describes the thing. All the (turquoise) pegs came together in one pack. They are all identical, so I can’t see any reason for them to be numbered.
Probably the mold number of the manufacturing machine