TVP and Metengr :
You are absolutely right with your comment about testing the material. But in the beginning I thought this would be a quicky : I allready did check with our materials engineer about this issue. He confirmed it was a brittle break and the only conclusion for him (at that time)...
Thank you all for replying. First thing I am going to do is order another batch of washer from another supplier and check if I can see any difference in breaking behaviour.
@ metngr : Surely I should send it to a competent metallurgical lab and get it analysed. However, my experience with...
Hello,
I have the following situation :
a little wheel (round 15mm.) is put on an axle (round 5) and retained by a retaining washer (Stainless steel, 1.4122, DIN6799, groove 3,2mm.) that fits on a groove in the axle.
After some while some of the retaining washers start to break brittle (no...
I am designing a sliding door runner system.
I should be very basic and low cost.
The top rails wil be made of Aluminium and the wheels of a plastic.
Is there a book / website / manual or whatever that can help me engineer the above parts regarding loads, strengths, frictions choice of...
thanks for your replies.
Would a skateboard wheel be injection moulded or would it be turned from rod?
(I 'd guess they would be made by turning, looking at the grooves on the outer surface)
Does anybody know what material skateboard wheels are made of ?.
I want to design some sliding gear for heavy doors, and the material skate board wheels are made of are of interest to me. If only I knew what material was used....
Hi Pud,
I have the moulding data sheet from the Chinese moulder.
It has temperatures measured on three points :
Temperature zone 1 250 deg(celcius)
Temperature zone 2 245
Temperature zone 3 240
It doesn't say where these temperatures are measured at.
I cannot find processing temperatures...
What is the effect of a (too) low melt temperature of PolyCarbonate ?
I have structural molded part. It doesn't break (short term) and its dimensions are ok.
But I have found that the melt temperature used of the PC is around 245 degrees celcius. It should be (if I am correct) around 300...
thanks all.
De part is under constant stress, so physical aging can be an issue.
However, some (!) of the parts do break brittle at initial bending. I cannot find a logical solution to that. To my logic, if it would be a design flaw, every part should break and it should break at the same weak...
Hallo Harry, and others....
I am going to order transparant samples, which I should be able to check with a polarization filter, whether there are some unusual stress concentrations. I also should put a part in the oven at 220 degrees, which should even out the stress concentrations. (That's...
thanks all for your replies.
I've done some research myself, and now the case is the following :
The part made of Lexan, should be fixed in an aluminium part. in fixed position, the lexan part is being elastically bent permanently. When I removed one of those parts the lexan part broke...
I am trying to gather as much information as I can. Therefore this mail :
I 2 have kinds of injection molded pieces of Lexan 143 R.
The color is black.
From both parts I have 40 samples from the injection molder.
2 out of 40 samples tend to break very easilly (britle break), without the normal...
