Author Topic: Plastic injection molding machine CAD files  (Read 2942 times)

pinolec

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Plastic injection molding machine CAD files
« on: September 14, 2017, 09:03:42 am »
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AURktman

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Re: Plastic injection molding machine CAD files
« Reply #1 on: March 28, 2018, 06:36:45 pm »
Is there any chance you have a list of supplies used to make this machine?  I am very interested in building one for our department to be able to do polymers research.  It would work well for our lab. 

pinolec

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Re: Plastic injection molding machine CAD files
« Reply #2 on: March 30, 2018, 10:22:27 pm »
Unfortunately, I did not keep the track of parts nor the suppliers. I think all have been sourced locally. Due to weight, it was the cheapest for me to source it this way. Let me know if you have a problem with sourcing parts. I will try to help.

Piotr

great10

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Re: Plastic injection molding machine CAD files
« Reply #3 on: November 21, 2018, 02:32:56 pm »
Hello there.
beautiful
I have some questions.
1. How to install the thermocouple of the nozzle end resistance.
2. How the mixer works in the hive.
3. supply hopper installation details. automatic feeding.
What did you use for the 4th piston pressure adjustment?
5. Does the 30x30 box profile rely on the working pressure
6. We can print maximum kac grams.
thank you

pinolec

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Re: Plastic injection molding machine CAD files
« Reply #4 on: November 21, 2018, 06:23:34 pm »
Hi,

Ad 1. For thermocouple on the nozzle, I have used the thermocouple sleeve which goes between the nozzle housing and heater band. I can't find them anywhere. If you can't find them you may modify the nozzle to place a hole for the thermocouple. Or make a small cavity to tightly fit small thermocouple between heater band and nozzle housing.  I wouldn't use heater band with a built-in thermocouple as there measure the temperature of the heater and not the nozzle housing.

Ad 2. The mixer makes the plastic to flow close to the heat source. This minimizes temperature difference in plastic. Otherwise, it would be hard to quickly heat the plastic uniformly.

Ad 3. I don't have detailed plans of the hopper and I am not 100% happy with it as it tends to spill little plastic here and there. I will make a few pictures later to show you I've made it.

Ad 4. I use a regulator and filter. I can only regulate the pressure in both pistons at once. I plan to separately control the pressure at both pistons. I also put flow regulator in line with injection action to regulate injection time.

Ad 5. Sorry but I don't understand this question. Try to put it in different words.

Ad 6. The most I tried was about 30g of plastic. I think it is capable of more.

great10

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Re: Plastic injection molding machine CAD files
« Reply #5 on: November 21, 2018, 07:23:22 pm »
Türkçe

Thank you for your answers.

- 6 question: 30x30 box profiles are deformed as a result of work?

- do you control the diameter of the hive with two resistors with one device? Can I learn the brand and code of this temperature controller?

- I couldn't understand what you wrote with a nipple resistance. Can you show with the picture?

- Is the mixer free in the bucket?

- I think of a separate differential pressure adjustment valve for two pistons. because I think the pressure pressure with the injection pressure is not the same. is it correct?


pinolec

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Re: Plastic injection molding machine CAD files
« Reply #6 on: November 23, 2018, 10:29:08 am »
Hi,

The 30x30X3mm profiles are good enough. I am not sure about 2mm wall profiles.
The temperature controller is rex-c100 and I use it with SSR 40A and K type thermocouple. Something like this https://www.aliexpress.com/item/REX-C100-Digital-Thermostat-Temperature-Controller-PID-thermometer-SSR-40DA-solid-state-Relay-K-Thermocouple-Probe/32857142330.html
The mixer is unattached in the barrel.

Sorry, but I didn't understand that:
- do you control the diameter of the hive with two resistors with one device?
- I couldn't understand what you wrote with a nipple resistance.

I think the google translator have a hard time to understand the context. I assume you use it.

The separate adjustments of the pressure for both pistons is a very good idea.

great10

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Re: Plastic injection molding machine CAD files
« Reply #7 on: November 23, 2018, 12:09:45 pm »
Thank you.

What kind of material did you use for the injection group? What materials (such as 4140)

Will there be any heat treatment? Will there be a certain hardness?

Is the pipe and piston honing / grinding process for surface quality


pinolec

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Re: Plastic injection molding machine CAD files
« Reply #8 on: November 26, 2018, 05:29:57 pm »
For injection barrel and plunger (anything that will contact with plastic) I used 304 stainless steel. I must mention that currently, I use a brass nozzle with a different shape than in the one in the project. The reason for this is that I found locally such a nozzle and with slight modification, it was ready to go. I was expecting it to fail quickly but it is holding up good.
There was no heat treatment whatsoever. No grinding or other special surface treatment was used.

great10

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Re: Plastic injection molding machine CAD files
« Reply #9 on: November 26, 2018, 07:07:09 pm »
[size=16px !important]Teşekkürler. namlu kovanı: parça için alüminyum veya bakır kullanmaya isteksizim. Işıl iletkenlik için iyidir.[/size][/font][/color][/size][size=16px !important]the other parts (in contact with molten plastic) fall as 4140 or stainless steel. is it suitable?[/size][/color][/size][/font][/color][/size][size=16px !important]Does the piston you use for the injection provide the necessary pressure and force?
How many bars of the injection piston needed?
What type of adjustment valve did you use for the piston?[/size]

pinolec

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Re: Plastic injection molding machine CAD files
« Reply #10 on: November 27, 2018, 11:49:43 am »
The barrel sleeve in the picture is made of aluminium and is working good. The other parts are stainless steel 304. I am not sure about 4140 steel. It may also work. My only concern would be corrosion which may form inside the barrel and release during injection. It may stain the parts. I don't have any experience with 4140 steel so you decide.
I mostly do low-pressure moulding and it has enough pressure and holding force. I have done some tests on HDPE but that was on the unfinished machine and it worked well.
The piston I have is rated up to 8bar - 116psi. I don't go above 3bar for low-pressure moulding.

For regulation, I use: https://www.amazon.co.uk/Yato-yt-2383-Regulator-Filter-90-CM3/dp/B01ERUEABI
For flow control: https://www.amazon.com/PneumaticPlus-Connect-Fitting-Controller-Straight/dp/B00BICDXTE

Shop around. You can probably get this cheaper locally or Aliexpress :)

great10

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Re: Plastic injection molding machine CAD files
« Reply #11 on: December 03, 2018, 07:53:06 pm »
Hello

I'm sorry if I disturbed you.

I have some questions for you.

Is there a connection diagram for pneumatic pistons?

How do you control the pneumatic pistons?

I want to use the system fully automatically. I'm thinking of getting a solenoid valve for that. What do you think of that?

Does the material melt into the molten material in the pipe not mix? Is the problem of melting plastic in the pipe during the injection and melting?

How many grams of material can you print?

Can we use a small piston automatic opening / closing system in the feeding section or can we get automatic material into the sleeve?


great10

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Re: Plastic injection molding machine CAD files
« Reply #12 on: December 03, 2018, 07:55:53 pm »
a question will also be the injection nozzle part. Can you put a picture for the breast band of your breast. especially how was the thermocouple installed here?
« Last Edit: December 03, 2018, 07:59:49 pm by great10 »

pinolec

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Re: Plastic injection molding machine CAD files
« Reply #13 on: December 05, 2018, 09:11:57 am »

I don't have a diagram for pneumatics connections but its just 2 valves connected like this:



This is a standard connection with 5/2 valve.

To have it fully automated I would recommend changing in the project way the barrel is kept aligned. Sometimes I have issues with nozzle slightly missing the mould hole. When operated manually it is not an issue for me as I can quickly correct this. Either add some linear rails and bearing to keep barrel straight or modify the mould hole and or nozzle shape for better self-allignment.
After fixing this issues it should be no problem to operate it automatically. Of course, you will have to add some ejectors and make a hole under the clamp plates.

This machine doesn't have a screw for mixing plastic as modern injection machines do. This limits the speed and/or amount of plastic injected. Lack of mixing screw result in plastic close to barrel walls will get to the desired temperature faster than the plastic in the centre of the barrel. To neutralise this effect the part inside the barrel blocks the centre of the barrel forcing plastic through channels close to barrel wall where plastic is heated more uniformly.

The most I injected was 30g. I assume it is capable of doing more but I never tried.

The material is fed automatically into the barrel by gravity.

I have found the type of thermocouple I am using on the nozzle.
https://www.pmseurope.com/products/thermocouple-ring-type?variant=7525656559667
They may even have the required size. See the picture below how it is installed on the nozzle.