Dan75
Posts: 3
Joined: Mon Jul 08, 2019 12:50 pm

Newbie needs help on selctinbg best material for part

Mon Jul 08, 2019 2:16 pm

Hi, I'm Dan, I am a newbie when it comes to 3d printing and want to pick your brains on choosing the best material for recreating a part from a record player.
The part is small in size and it is made out of a hard, non flexible plastic. It has to be quite precise as it sits mounted on an axle.
The old part has become brittle over the years and does not stay in position as the screw in it doesn't hold any more due to the cracks in the plastic.
My gut feeling is to go with ABS as its rigid and strong but it seems that it is prone to shrinking, so I wonder what to do when it is printed and doesn't have the correct inner diameter to slide over the axle it should sit on.

Dan

ps; I do not posses a 3D printer myself, I'll have to outsource.

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dkightley
Posts: 1992
Joined: Tue Mar 10, 2015 3:09 pm

Re: Newbie needs help on selctinbg best material for part

Mon Jul 08, 2019 4:25 pm

There's plenty of material comparisons on the internet that are worth a read of.

One on the S3D site is here: https://www.simplify3d.com/support/materials-guide/
Doug Kightley
Volunteer at the National Tramway Museum http://www.tramway.co.uk
Railway modeller and webmaster at http://www.talkingtgauge.net

wirlybird
Posts: 1139
Joined: Sun Jul 17, 2016 12:32 pm

Re: Newbie needs help on selctinbg best material for part

Tue Jul 09, 2019 5:53 am

Dan75 wrote:
Mon Jul 08, 2019 2:16 pm
Hi, I'm Dan, I am a newbie when it comes to 3d printing and want to pick your brains on choosing the best material for recreating a part from a record player.
The part is small in size and it is made out of a hard, non flexible plastic. It has to be quite precise as it sits mounted on an axle.
The old part has become brittle over the years and does not stay in position as the screw in it doesn't hold any more due to the cracks in the plastic.
My gut feeling is to go with ABS as its rigid and strong but it seems that it is prone to shrinking, so I wonder what to do when it is printed and doesn't have the correct inner diameter to slide over the axle it should sit on.

Dan

ps; I do not posses a 3D printer myself, I'll have to outsource.
PLA would work and so would PETG and ABS.
ABS isn't going to shrink much at all for a small part.
As for holes in the part you will probably have to drill them to size regardless of the material.

billyd
Posts: 184
Joined: Mon Jan 19, 2015 12:13 pm

Re: Newbie needs help on selctinbg best material for part

Tue Jul 09, 2019 1:00 pm

I'm a big fan of ABS but in this case PLA would probably be fine and is certainly easier to print.

Since there is a screw into threads, you might consider using a heat set insert instead of threading into the plastic directly. If you are not familiar with them, what's involved is printing a hole appropriately sized for the insert (per the insert's specs) and then pressing the insert in after the print is complete (with a soldering iron set to a temperature of 400F for PLA or 500F if using ABS). The insert will last practically forever versus threading into plastic which is dicey and won't last long, as you've seen. You can get heat set inserts from eg mcmaster carr or similar online stores and they come in nearly every thread size and pitch under the sun.

Dan75
Posts: 3
Joined: Mon Jul 08, 2019 12:50 pm

Re: Newbie needs help on selctinbg best material for part

Tue Jul 09, 2019 1:29 pm

Hi, thanks for the answers!
To make things a bit more understandable I've made sone pictures of the particular part.
IMG_7569.JPG
IMG_7566.JPG
IMG_7565.JPG

Dan75
Posts: 3
Joined: Mon Jul 08, 2019 12:50 pm

Re: Newbie needs help on selctinbg best material for part

Tue Jul 09, 2019 1:35 pm

Do I need some kind of bed added in the 3d file so it can be printed ?
(due to its small size; hole diameter is 0,199 inch, the outside is 0,315 inch, the the total height is 1,02 inch including the little lever arm.)

billyd
Posts: 184
Joined: Mon Jan 19, 2015 12:13 pm

Re: Newbie needs help on selctinbg best material for part

Thu Jul 11, 2019 11:51 am

You'll have to use supports. Place the flat portion of the model towards the bed when slicing (like in your first picture), and add supports for any overhangs or ledges that are more than 45 (and up to 90 degrees) off vertical. (Depending on how well your printer handles overhangs.) To be safe anything more than 45 degrees is a good starting point for supports. Although some printers can handle overhangs well up to 65 degrees.

Also since the part is very small, it's probably best to print several (4 or more) of them to allow the part to cool sufficiently as it is printed. This is the easiest way to handle that. (printing multiple parts). There are other more sophisticated ways but I find this works well and is easiest. Turn off optimization in the layer tab so it doesn't repeat a layer on the same part. Also you should probably print the part at a small layer height (.1mm)

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