Injection molding barrel part

Hi everyone,

We are making a version of this machine to do some small production and testing in our workshop.
Now we are constructing the barrel. And this raises a question or 2.
First question is about the tolerance between the tube and the solid bar going in?
It seems that the tube used commonly has an inner size of 27mm and the bar is 26.
Does this cause a problem for anyone?

Thanks in advance!
Nathan

Hey @nathan wierink,

26×34 mm tube should be available in the Netherlands, we found some around eindhoven.
For the plunger we used a 26x2mm tube.
Would be Nice to find 26×34 cause it’s used un the extruder as well.

Groeten Kees

1mm is ok, more than 1mm is not desired, otherwise the plastic will slip through the gap between the drill bit and the pipe.

Hello Kees,

Thank you for your reply!
The tube dave is referring (standard heating/water pipe) to I could only find with an inner diameter of 27mm. Outer diameter is 34mm.
But my main question is if it is ok to have some tolerance between the inner rod and outer tube?
I’ve now a tolerance of 1mm app. And in the movie it appears to also have some tolerance.
Any help is greatly appreciated.