Hi All,
I'm getting ready to make the next version of my DIY press. Before I get started, I have some questions. I'm hoping some of the pro's here can help. The 7" stampers I'm using for my testing are old and I'm not sure how standard they are. They are 10" in diameter with a 1" center hole. The stampers have been formed into what I believe is a typical 7" profile, but I'm not sure how they would be mounted to the press. They have been formed such that there are two higher ridges. One peak is at the finished diameter of the disc (6 7/8") the other is at 9 1/4". This last ridge creates a ramp at the edge of the disc.
1. Is the mounting surface of the press flat or is it machined to conform to the surface of the stamper?
2. When the upper and lower stampers are pressed together, do the highest surfaces meet while under pressure?
3. Are the stampers designed to flex a bit and/or move or are are they held in a rigid manner during the press operation?
4. Is the 1.5" center holed formed during the pressing or is this done as an after press process?
5. I assume there is some sort of bushing used to attach the upper and lower stampers to the press. Are they a male and female pair or are they identical (e.g. both 1.5" in diameter).
6. Was there ever a printed reference/operation manual available for any of the commercial presses made by various manuacturers?
I hope I'm not being a pain asking these questions. I'd like to avoid any costly errors when I move to the level with my design.
Mark
Some Questions on Pressing
Moderators: piaptk, tragwag, Steve E., Aussie0zborn
ok
here we go
Both moulds upper an lower are exactly the same
The stampers are fixed hard in the centre but allowed to expand contract on the perimeter in a round about way If the centres are not fixed hard one gets records running off centre
The faces are not allowed to "kiss" or you need new stampers
the pvc flowing out so as to make the "flash" makes sure of that
all 7" are made with the standard 9/32" hole It is punched out afterwords
Some people do a removable centre but it is punched out regardless so as to leave 3 spots still attached to the record so it can be easily pushed out
The moulds have the profile that is liked required wanted whatever on them
The stampers are merely formed so as to have a centre to suit the bush and mould the perimeter is formed at around the 30 degree angle so as to be held down by the outer ring
They get formed on the first pressing so as to conform to the moulds therefore one needs to hold them hard in the centre and let them "move" on the perimeter
The bush and pins which hold the stampers in place are quite varied according to the press they are to be mounted on
The bushes may be indentical in most cases but the pins are not so it depends
When you find a printed reference it will be specific for a press but I have yet to see this so far at least on the net
Hope this helps
By the way there are more issues on pins and bushes than any other area of pressing
Quite a pain on the proverbial
May be you get the Idea when you get these bits and bobs that they are on the way to you Mark
Cheers
here we go
Both moulds upper an lower are exactly the same
The stampers are fixed hard in the centre but allowed to expand contract on the perimeter in a round about way If the centres are not fixed hard one gets records running off centre
The faces are not allowed to "kiss" or you need new stampers
the pvc flowing out so as to make the "flash" makes sure of that
all 7" are made with the standard 9/32" hole It is punched out afterwords
Some people do a removable centre but it is punched out regardless so as to leave 3 spots still attached to the record so it can be easily pushed out
The moulds have the profile that is liked required wanted whatever on them
The stampers are merely formed so as to have a centre to suit the bush and mould the perimeter is formed at around the 30 degree angle so as to be held down by the outer ring
They get formed on the first pressing so as to conform to the moulds therefore one needs to hold them hard in the centre and let them "move" on the perimeter
The bush and pins which hold the stampers in place are quite varied according to the press they are to be mounted on
The bushes may be indentical in most cases but the pins are not so it depends
When you find a printed reference it will be specific for a press but I have yet to see this so far at least on the net
Hope this helps
By the way there are more issues on pins and bushes than any other area of pressing
Quite a pain on the proverbial
May be you get the Idea when you get these bits and bobs that they are on the way to you Mark
Cheers
Last edited by mossboss on Wed Dec 29, 2010 3:38 pm, edited 1 time in total.
Chris
Hi Chris,
Thanks! That was super! Looking forward to getting the odds and ends. I'm sure those along with the helpful hints will allow me to get things up and running.
Is there anything that limits the total travel of the press, or is it just based on pressure, time, and temperature?
Are the outer rings machined to match the 30 degree slope of the stamper edge?
Based on your answer, I assume that the rings only lightly clamp the edge and help provide a guide path for expansion of the stamper. Is this correct?
Mark
Thanks! That was super! Looking forward to getting the odds and ends. I'm sure those along with the helpful hints will allow me to get things up and running.
Is there anything that limits the total travel of the press, or is it just based on pressure, time, and temperature?
Are the outer rings machined to match the 30 degree slope of the stamper edge?
Based on your answer, I assume that the rings only lightly clamp the edge and help provide a guide path for expansion of the stamper. Is this correct?
Mark
OK next lot of Q & A
No issue by the way so keep going
Opening or daylight as it is called of presses was always very short so as to limit travelling time
Even book style presses had just enough space for the pair of moulds to slide in and and out so they moved about 1-2" maximum so as to close/open
As quite a few presses had only a high pressure low volume pump closing speed was not that great any way
Unless you where running with a 10-15 kw motor at 3000 rpm or there abouts
Keep in mind that the ram is in the vicinity of 12-14" depending on system pressure so as to get the 100-110 tonne required to press a record, that is a lot of oil to pump in when you are running at say 6-8 cc per rev on the pump with about a 3 kw motor on the pump which was about right at the time with a single pressure system)
(By the way they are commonly known as "coining" presses
Accumulators and high volume low pressure pumps coupled to a high pressure pump speeded up the movements so as to make them faster but not in all cases or by all manufacturers
The europeans did a lot of the pioneering while US based manufacturers did very good improvements but never went for the high speed stuff
High speed with larger oppenings was a bit of a ncessity as the presses became automated they had to accommodate a puck at around the 1-1.75" high plus the label arms that had to go inside the open moulds in some presses
Added to this is another 1/2" plus a bit of clearance so around the 3"-4" inches of opening became a necessity
To maintain speed they adopted Switching from l/p to h/p oil pressure having full pressure only applied at the last 1/2" on the last bit of travell as the moulds come together
But that was much later in press development
It was really a case of speed heat retention lower cost of hydraulic components and a whole host of other considerations as expalined above
Outer Rings
There is about as much variation there as one can imagine Alpha uses a bayonet style of fixng spun out of fairly thin metal They also used another style of quick type of holding ring like a click and hold style cap
Columbia glued they stampers down with some gung that only needed a holding ring on the outer using a segmented type of holder with an allen screw in each segment
Lened a full holding down ring with allen screws again as well as a host of other varieties
No hard and fast rules here
One thing they all have in common is the fact that the holding ring is a lot lower than the mating surfaces of the moulds so as to make sure that flash does not get in between the stamper and the ring
At the end of the day since there is around a 1.2-1.5 mm expansion contraction of the moulds during heating and cooling you want to have the stamper moving along with it If the stamper is held very tight on the rings you can see them buckling when the heat cycle comes on quite obvious
Since they are thin they will move quite much earlier than the solid mass of steel that the moulds are made off so they need some freedom
So long as they hold down the outer rim firm it is sufficient
Also if there is a malfunction and the press opens before the record cools down, that it is good bye stampers as they get ripped right out of the holding rings and sometimes the centre bush
Not nice but part of pressing
Ok next lot of q's
Cheers
No issue by the way so keep going
Opening or daylight as it is called of presses was always very short so as to limit travelling time
Even book style presses had just enough space for the pair of moulds to slide in and and out so they moved about 1-2" maximum so as to close/open
As quite a few presses had only a high pressure low volume pump closing speed was not that great any way
Unless you where running with a 10-15 kw motor at 3000 rpm or there abouts
Keep in mind that the ram is in the vicinity of 12-14" depending on system pressure so as to get the 100-110 tonne required to press a record, that is a lot of oil to pump in when you are running at say 6-8 cc per rev on the pump with about a 3 kw motor on the pump which was about right at the time with a single pressure system)
(By the way they are commonly known as "coining" presses
Accumulators and high volume low pressure pumps coupled to a high pressure pump speeded up the movements so as to make them faster but not in all cases or by all manufacturers
The europeans did a lot of the pioneering while US based manufacturers did very good improvements but never went for the high speed stuff
High speed with larger oppenings was a bit of a ncessity as the presses became automated they had to accommodate a puck at around the 1-1.75" high plus the label arms that had to go inside the open moulds in some presses
Added to this is another 1/2" plus a bit of clearance so around the 3"-4" inches of opening became a necessity
To maintain speed they adopted Switching from l/p to h/p oil pressure having full pressure only applied at the last 1/2" on the last bit of travell as the moulds come together
But that was much later in press development
It was really a case of speed heat retention lower cost of hydraulic components and a whole host of other considerations as expalined above
Outer Rings
There is about as much variation there as one can imagine Alpha uses a bayonet style of fixng spun out of fairly thin metal They also used another style of quick type of holding ring like a click and hold style cap
Columbia glued they stampers down with some gung that only needed a holding ring on the outer using a segmented type of holder with an allen screw in each segment
Lened a full holding down ring with allen screws again as well as a host of other varieties
No hard and fast rules here
One thing they all have in common is the fact that the holding ring is a lot lower than the mating surfaces of the moulds so as to make sure that flash does not get in between the stamper and the ring
At the end of the day since there is around a 1.2-1.5 mm expansion contraction of the moulds during heating and cooling you want to have the stamper moving along with it If the stamper is held very tight on the rings you can see them buckling when the heat cycle comes on quite obvious
Since they are thin they will move quite much earlier than the solid mass of steel that the moulds are made off so they need some freedom
So long as they hold down the outer rim firm it is sufficient
Also if there is a malfunction and the press opens before the record cools down, that it is good bye stampers as they get ripped right out of the holding rings and sometimes the centre bush
Not nice but part of pressing
Ok next lot of q's
Cheers
Chris
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Aussie0zborn
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Hi,
Great picture. Helps alot. I think Chris has some center bushes in the care package he's sending out to me. But if I get stumped, I'll contact you. One thing is not clear in the picutre. It looks like both bushes are identical. In my mind, I assumed there would be a male and female bush to form the center hole. Am seeing this correctly? I am also correct that the press has some sort of adjustable mechanical stop to assure that the finsihed record is of the proper thickness?
Mark
Great picture. Helps alot. I think Chris has some center bushes in the care package he's sending out to me. But if I get stumped, I'll contact you. One thing is not clear in the picutre. It looks like both bushes are identical. In my mind, I assumed there would be a male and female bush to form the center hole. Am seeing this correctly? I am also correct that the press has some sort of adjustable mechanical stop to assure that the finsihed record is of the proper thickness?
Mark
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Aussie0zborn
- Posts: 1828
- Joined: Sat Mar 11, 2006 8:23 am
- Location: Australia
- Contact:
This is a Finebilt press with book-type moulds (ie: they are hinged on one side - the rear). It does look like there are four stops which I've never seen before.
1. The centre bushes contain the pins. The top pin is of the right diameter to make the hole and goes 2/3rds the way through the record. The bottom pin is a few thousandths of an inch bigger in diameter and goes through 1/3rd of the record. The top pin cuts against the bottom pin, squeezing the vinyl out, hence the bottom pin being bigger in diameter. The top pin is fixed and the bottom pin slides up to fix the label to it and is pushed in when pressing. It pops up again for the next cycle. If it didn't pop up it would be too short for you to fix a a label to it.
2. Another method is that used by SMT. The top bush has no pin - just a flat face. The bottom pin contains a long sliding pin. The vinyl pattie with a label on each side is dropped onto the pin which meets the top bush to create a "seal" before the vinyl is pressed around it.
3. Another method was that used by CBS. The top bush has a hole in it, The bottom bush has a long tapered pin which is fixed. Again the vinyl pattie with a label each side is dropped on the pin and as the press closes, the tapered pin is forced inside the hole of the top bush to create a "seal" before the vinyl is pressed around it. There is no movemement of any pins and so you dont need an air cylinder under the mould to push the pin up for each cycle.
4. Another method was the original Alpha Toolex method which leaves a slug that needs to be removed each time. The top pin is longer than usual and fixed. It has a dome head. The bottom pin is pushed in on the pressing cycle as the top pin is so long, it pushes the vinyl trapped in the hole way from the record making a slug. When the press opens and the record is removed the pin pops up with a slug sitting on it. This needs to be removed. This was easy to modify to method # 1 above. In their automatic press, Alpha Toolex used a sliding pin on the top and bottom bush.
5. Hydraulic presses amde by Johns in Australia that were converted to record presses used method number one. The bottom pin would slide up when activated by a foot pedal that actuated and air cylinder, so this need not be timer controlled if you are doing low volume production.
Im sure there are a few other methods.
In the photo of the Finebilt press above it looks like the top pin is the sliding pin with a flat face while the bottom pin is the fixed pin with a concave face which does the "cutting". The sliding pin can be either top or bottom depending on the brand of press. Having it on top as with Fabel presses means the air cylinder that drives it is easily accessible for maintenanace. Having it in the bottom as with Alpha Toolex presses means that you need to remove the bottom mould to perform any maintenance on the air cylinder.
To keep it simple you might look at using the CBS method. Good luck.
1. The centre bushes contain the pins. The top pin is of the right diameter to make the hole and goes 2/3rds the way through the record. The bottom pin is a few thousandths of an inch bigger in diameter and goes through 1/3rd of the record. The top pin cuts against the bottom pin, squeezing the vinyl out, hence the bottom pin being bigger in diameter. The top pin is fixed and the bottom pin slides up to fix the label to it and is pushed in when pressing. It pops up again for the next cycle. If it didn't pop up it would be too short for you to fix a a label to it.
2. Another method is that used by SMT. The top bush has no pin - just a flat face. The bottom pin contains a long sliding pin. The vinyl pattie with a label on each side is dropped onto the pin which meets the top bush to create a "seal" before the vinyl is pressed around it.
3. Another method was that used by CBS. The top bush has a hole in it, The bottom bush has a long tapered pin which is fixed. Again the vinyl pattie with a label each side is dropped on the pin and as the press closes, the tapered pin is forced inside the hole of the top bush to create a "seal" before the vinyl is pressed around it. There is no movemement of any pins and so you dont need an air cylinder under the mould to push the pin up for each cycle.
4. Another method was the original Alpha Toolex method which leaves a slug that needs to be removed each time. The top pin is longer than usual and fixed. It has a dome head. The bottom pin is pushed in on the pressing cycle as the top pin is so long, it pushes the vinyl trapped in the hole way from the record making a slug. When the press opens and the record is removed the pin pops up with a slug sitting on it. This needs to be removed. This was easy to modify to method # 1 above. In their automatic press, Alpha Toolex used a sliding pin on the top and bottom bush.
5. Hydraulic presses amde by Johns in Australia that were converted to record presses used method number one. The bottom pin would slide up when activated by a foot pedal that actuated and air cylinder, so this need not be timer controlled if you are doing low volume production.
Im sure there are a few other methods.
In the photo of the Finebilt press above it looks like the top pin is the sliding pin with a flat face while the bottom pin is the fixed pin with a concave face which does the "cutting". The sliding pin can be either top or bottom depending on the brand of press. Having it on top as with Fabel presses means the air cylinder that drives it is easily accessible for maintenanace. Having it in the bottom as with Alpha Toolex presses means that you need to remove the bottom mould to perform any maintenance on the air cylinder.
To keep it simple you might look at using the CBS method. Good luck.
Hey All
There is no thickness adjustment in these moulds These are not "stops" They are cushions so as to stop the moulds hitting hard when they close and to facilitate separation/opening of the dies vertically or straight up when the press opens
The bottom four bushes are spring loaded or they may have a hard rubber inserts under them They are larger that the four solid pins on the top
They give way under pressure by getting compressed under the presure exerted from the press when the moulds are driven back between the plattens
When the press opens they push the moulds apart before they get slid out from the plattens
On the manual alphas this cushion is incorporated on the press itself Since there is a retraction of the ram straight down by about 1-1.5" before the press swings open the top part of the platten
Same like on the tcs presses and the fabels On the Finebuilts it is done on the mould carriers as the moulds are fastened on to the carriers rather than the plattens of the press so it has to be there or else they will just stay closed since there is nothing to open them apart from the sickle like arm but that will exert a radial movement and it will just break as the guide pins will not allow the molds to open If you have a close look at the guide pins you will notice that they are rounded and quite short so as to prevent that as much as possible but it is not unknown that they snap clean if the molds do not open up or the ram that pushes and retracts them just give up standing still or goes into presure relief so as to prevent damage on a well adjusted machine
No big deal really just another method to achieve the desired result
However it is not thickness adjustment thats for sure
Cheers
There is no thickness adjustment in these moulds These are not "stops" They are cushions so as to stop the moulds hitting hard when they close and to facilitate separation/opening of the dies vertically or straight up when the press opens
The bottom four bushes are spring loaded or they may have a hard rubber inserts under them They are larger that the four solid pins on the top
They give way under pressure by getting compressed under the presure exerted from the press when the moulds are driven back between the plattens
When the press opens they push the moulds apart before they get slid out from the plattens
On the manual alphas this cushion is incorporated on the press itself Since there is a retraction of the ram straight down by about 1-1.5" before the press swings open the top part of the platten
Same like on the tcs presses and the fabels On the Finebuilts it is done on the mould carriers as the moulds are fastened on to the carriers rather than the plattens of the press so it has to be there or else they will just stay closed since there is nothing to open them apart from the sickle like arm but that will exert a radial movement and it will just break as the guide pins will not allow the molds to open If you have a close look at the guide pins you will notice that they are rounded and quite short so as to prevent that as much as possible but it is not unknown that they snap clean if the molds do not open up or the ram that pushes and retracts them just give up standing still or goes into presure relief so as to prevent damage on a well adjusted machine
No big deal really just another method to achieve the desired result
However it is not thickness adjustment thats for sure
Cheers
Chris
And another of the molds in question or very similar any way Watch around the 3 m mark onwards
http://www.youtube.com/watch?v=PVrM-dEXQ3A&feature=related
Cheers
http://www.youtube.com/watch?v=PVrM-dEXQ3A&feature=related
Cheers
Chris
Mark This one shows the holding down rings quite well in the first 15 seconds or so its on an Auto 1202 Alpha
http://www.youtube.com/watch?v=nl0bMxCi1qE&feature=related
http://www.youtube.com/watch?v=nl0bMxCi1qE&feature=related
Chris
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Aussie0zborn
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Yes good point - the moulds need to separate vertically before they open. The Alpha manual press has four return springs under the platen to separate the moulds and clear the locating pins before the head tilts to open.mossboss wrote: There is no thickness adjustment in these moulds These are not "stops" They are cushions so as to stop the moulds hitting hard when they close and to facilitate separation/opening of the dies vertically or straight up when the press opens
Yes Mike
That is correct but not quite enough as the springs do get "lazy"
I have now installed a little timer and a delay of a few seconds on the 3 presses so as to allow the bottom ram to get out of the way before the top swings open
This was easy on the later machines but the oldest one that still had the solid bar to control the hydraulics had to be modified extensivelly so as to achieve that
It now has an air cylinder that operates the closing valve of the press activated by the closing of the gate just like the later model
It had to be done with an air cylinder and a little solenoid valve as the electronics on that machine are still valve or tube operated with pmg like relays
Nowhere to take a signal from easily
This valve/tube controller with a myriad of resistors on rotating time selector switches it is still working flowlessly after all these years
It was made in 1967 and the control box has never given any problem whatsover
Quite amazing really
It must by now clicked 10's of million's of operations and still going strong
I have a bit of a chuckle when I see spec's for modern components that anounce things like 5 million operations before failure
Argh well here is living proof of Swedish technology
Cheers
That is correct but not quite enough as the springs do get "lazy"
I have now installed a little timer and a delay of a few seconds on the 3 presses so as to allow the bottom ram to get out of the way before the top swings open
This was easy on the later machines but the oldest one that still had the solid bar to control the hydraulics had to be modified extensivelly so as to achieve that
It now has an air cylinder that operates the closing valve of the press activated by the closing of the gate just like the later model
It had to be done with an air cylinder and a little solenoid valve as the electronics on that machine are still valve or tube operated with pmg like relays
Nowhere to take a signal from easily
This valve/tube controller with a myriad of resistors on rotating time selector switches it is still working flowlessly after all these years
It was made in 1967 and the control box has never given any problem whatsover
Quite amazing really
It must by now clicked 10's of million's of operations and still going strong
I have a bit of a chuckle when I see spec's for modern components that anounce things like 5 million operations before failure
Argh well here is living proof of Swedish technology
Cheers
Chris