Extruder Temperature

[Flight13_duplication]

HI!

I have I question, maybe you can help me:

I am pressing 180gr LPs on my Toolex 1202. The temperature setting of the extruder is: 115, 125, 135.

When I am pressing some minutes, the temperature is rising to 130, 135, 140. The 3 zones are cooling all the time, but due to the massive output, the extruder heats up. When the circle time goes up (maybe when I increase the cooling time) the temperature of the 1st zone of the extruder goes down for, maybe 2-3 degrees within 2 or 3 records. And when I change the stampers, it takes only maybe 1 minute and the temperature is again fine. Like the settings.

So, I have 2 questions:
1.: Is it a problem when the temperature of the first zone (and the others) are so high? Can it damage the screw?
2: what can I do? Is a variable frequency drive a solution as the speed of the motor and the forces on the screw are not so massive?

For example I know that a pressing plant reduced the extruder speed at their 180g machine 25%.

What do you think?

Thanks and have a nice evening.

Cheers.

Bieber

[andybee]

Hi Bieber!
Well, not your first post, the 30th one
As I remember from dismantling the ZYX Vinyl Factory, there are different
Extruder screws available or possible. You will need a screw, that can
feed more material at the same time.
The basic principal of an extruder is, to generate the heat with compression
of the material to carry.
It also can help, if you have a bigger exit hole for the material, so the compression
is not as high.
or you try this:

[Flight13_duplication]

HI Andi,

yes, I must be really desperate if I post here again...

Thanks, well yes, this machine can solve all of my problems. And it works with low voltage. Great.

Thanks for your answer. I guess it will be hard to find information about other screws but it is a start. I will work on this.

The extruder has now around 10 secounds break between the records. I guess, combined with the massive output, this is not long enough.

Thanks!

Cheers.
Bieber

[mossboss]

The simple answer is that you need a new screw and or a barrel mate I doubt that the barrel will need replacement but the screw from your post seems to be worn so the compound is passing the flights of the screw forming a sleeve over it
The material is heated by friction rather than the heat provided by the heating elements
The fact is that the material is sticking to the screw rather than the barrel therefore uncontrolled temperature or as it is called heat runaway is the indication of a worn out screw
Also if the speed of the extruded has been speeded up in the past by a different size pulley not uncommon the motor will be drawing a lot more current than the 7.5 kW that's rated, that's if it is running at a very much higher speed than design speed
You should be able to do a 200 gram puck in around the 15 seconds as the standard speed for a 150 gram puck is around the 10 seconds any faster than that it is running to fast another cause of friction and uncontrolled temperature during extrusion so check the current draw of the motor
Changing the pulleys to slow it down is no big deal standard pulleys and taper bushes are around the 60 euro's if that fails to fix it than its a new screw
Best

[Flight13_duplication]

Hi Chris,

thanks for your help. Well I will try to slow the motor down.

But as long as it is like it is: Do you think it is bad for the screw to have it like I have it now? And do you think it is bad for the records?

Cheers.

BIeber

[mossboss]

If the screw is already worn out it will have no further detriment to the operation, unless of course it's very bad and it is scrapping the sides of the barrel
In so far as weather it is bad for the records that's easy to tell
Make a puck and take it out of the former
Leave it on the bench and see if it increases in size like swelling up
If it does the compound is gassing off in other words overheated
if it stays the same size as it was formed that there is no issue
If it swells of course you will have a lots of bad records and a lot of rejects
Slow the machine down first and see how you get on check the motor load before you change pulleys and after also the overload should be set around 1/2 an amp bellow the maximum current the motor draws as per the specification plate
Let us know how you get on
If you need to get a new screw pm me for details
Best

[leethal]

Hi Bieber!
Well, not your first post, the 30th one
As I remember from dismantling the ZYX Vinyl Factory, there are different
Extruder screws available or possible. You will need a screw, that can
feed more material at the same time.
The basic principal of an extruder is, to generate the heat with compression
of the material to carry.
It also can help, if you have a bigger exit hole for the material, so the compression
is not as high.
or you try this:

hahahaha you found my diy extruder! Its evolved a bit since then

[montalbano]

Hey Bieber
The rising of the temperature on old extruders is a classic, especially when you need to make a big puck (230-240g for a 180g record, or even less - it depends on the unloading rings you are using).
As far as you manage to make the puck in time, and stay within the temperature ranges which the compound you are using can stand, no problem.
The problem begins when the extruder gets too slow. This happens because - most likely - the barrel is corroded in some points, and the compound "falls down" and brings extra heat to the compound which is being collected in the lower part of the screw.
Now, if you look at the drawing of a screw, and consider a fixed rotation of the screw driven by the motor, you will immediately notice that its inner diameter (let's call it "nut") changes from bottom to top. The bottom part (the one near the gearbox) has a remarkable gap between the nut and the edge, in order to collect a wide load of compound when rotating. Then there is the compression zone, where the heated compound gets compressed and turns into a sort of paste. And then there is the edge when the paste is taken to the desired temp.
If you have a worn out barrel, which in my view is your case, some of the compound is falling from the compression zone down to the collecting zone, bringing extra heat which the Plastomatics (or similar instruments) are unable to correct in time, and slowing down the puck extrusion time. I might think it's the screw too, but this would be uncommon: most likely it's the barrel.
I have faced this problem several times, and here in Milan there is a company which can rectify and sand the barrel and take the screw to the proper size so that it fits the barrel with a minimized play. Diameters will slightly change, because of course the barrel will get slightly smaller, and the screw slightly bigger, but I can guarantee that it works and it's cheap too.
Otherwise, yes, you can buy a new screw. But if the screw is a standard size screw, and the barrel is worn out, then you will have your problem unsolved.

[Flight13_duplication]

HI!

The temperature returned to be normal.

Reason for the increased temperature was a piece of metal in the screw. It must have been in the barrel for months. I heard it, but I could not specify the noise I have heard. Now I know what it was... You can also see a little damage of it on top of the screw. 1 month ago I had the first crash with metal during pressing some records. I repaired the moulds and had the same crash last week again. After repairing the moulds again, I opened the barrel and took a look at the screw. The srew is fine.

So, now everything is working again and the temperature of all 3 zones is fine, too.

Thanks for your help anyway.

Cheers.

Bieber