Newbie who needs guidance how to print cassette player gears and idlers

[fred_dot_u]

Does this look like your objective?

I've left the axle solid, as there were no dimensions in the post for the axle hole diameter.

idler.jpg

In an earlier post, you ask about which scanner to buy. If you mean a 3D scanner aimed at 3D printing, you'd be spending hundreds of dollars for something that could accomplish this.

One option to consider is to use photogrammetry. There are some free sites, although I've not experienced them. One takes a series of photographs from all angles and the software creates a 3D model. The file generated typically has plenty of background "litter" and often leaves holes in the model. Those holes require repair in modeling software with which one should have a strong background. The results of this process and other scanning methods are not particularly well suited for dimensionally critical parts. The scanning systems that can manage those parts will cost thousands of dollars.

$fn = 90; // smoother surface of cylinders
axle_diameter = 2;
disk_thick = 1;
disk_diameter = 10;
short_stem_height = 2;
long_stem_height = 5;
stem_diameter = 2;
addabit = 0.0625; // provide overlap to avoid z-fighting

module assembly(){
    cylinder(h = disk_thick, d = disk_diameter); // main disk
    translate([0, 0, -short_stem_height + addabit]) // move short stem below disk
    cylinder(h = short_stem_height + addabit, d = stem_diameter); // short stem
    translate([0, 0, disk_thick - addabit]) // move long stem above disk
    cylinder(h = long_stem_height + addabit, d = stem_diameter);
}
assembly();

[hdtvjeff]

Thank you so much !!!!The axle hole is 1.5 mmIf I needed to change the height of the base and make it pully like that can hold a tire instead how would that accomplishedI can muster up a few hundred on my pensionCan you recommend any model on AMazonAlso, your opinion on the scanner I bought?Again,Thank you so very, very muchI do not mind zelle. venmo to thank you going forward if I need your helpKindest regards,jeff

[fred_dot_u]

If the axle hole is 1.5 mm that can be easily incorporated into the model code. The same applies to creating a groove or pulley, which would be done by generating a torus and subtracting it from the disk. I would have to have the dimensions of the disk height and the depth and width of the groove. If the drive pulley is an o-ring, the depth would be half of the width, making things a bit easier. There's a concern about the axle. The outer diameter is 2 mm and the inner diameter is 1.5 mm, which leaves 0.25 mm for the wall thickness. The printer will print a minimum wall thickness of 0.4 mm which means the slicer software (Cura in your case) will print nothing for those portions.

In the application you mention, a cassette player pulley, is there enough clearance around the axle to increase the diameter to 2.3 mm or larger? Creating parts that are multiples of nozzle diameter provides for a better constructed print.

You ask about the "scanner" but if you mean printer, I have no opinion regarding that model.

For a part this small, the axle components are going to be too fragile when printed on your model printer and too fragile when printed on my model printer. I suggest that the dimensions become completed when you get your calipers, that a test model be printed and checked for fit, but not installed. Once the design is matched to correct dimensions and fit, have the model printed by an online resource and use SLS printing in nylon. Much stronger and not too expensive for a single part.

If the axle hole is to allow a longer metal shaft to pass through, the fragility of the pulley is not as much of a factor, as the shaft will support those portions.

[hdtvjeff]

Thank you so much for al your wonderful advice I will research alternate ways to "scan" an image Maybe search too for a new 3d printer that does vinyl will attempt to use unopened printer to test drive it Since I am getting into restoration of vintage equipment which contains little plastic gears, pulleys and idlers maybe it pays to invest in something better ,Question, in the code you were so nice to provide, can you add axle (stem) hole of 1.5mm all the way through?I guess the code you sent I incorporated into the supplied software and then print, should be exciting Thank youJ eff

[fred_dot_u]

You won't be able to print vinyl, to the best of my understanding, but I think you might mean nylon. To print nylon with a filament printer, you'll need a fully enclosed chamber and an all-metal hot end capable of high temperatures as well as a heated bed to round out the specifications. Consider to search for nylon filament and read the specifications. For the small size of the components you're considering to print, you'll want to have a 0.2 mm nozzle as well. Most printers come standard with 0.4 mm nozzles and the latest rage is to use 0.6 and larger nozzles for faster larger objects.

The code I sent is an example of how to create this specific part in OpenSCAD. It cannot be used in any slicing software to produce useful results. OpenSCAD is a 3D creation program, which allows one to create models in a parametric manner, then export as STL files for printing. Cura will accept an STL file.

I recommend that you locate YouTube videos for beginner 3D printer owners, as your questions indicate that you are missing key aspects of using a 3D printer. I recommend this action prior to opening the box in which the printer is contained. You MUST have the basics before you continue on your journey.

The following code contains the modification you requested, as well as a groove around the pulley, arbitrarily sized to one-third of the thickness of the pulley. Keep in mind again that the material around the axle hole cannot be printed on a filament printer with a 0.4 mm nozzle and should not be printed with a 0.2 nozzle, as the result will be a single line of filament and be exceedingly weak.

$fn = 90; // smoother surface of cylinders
axle_diameter = 2;
axle_hole = 1.5;
disk_thick = 1;
disk_diameter = 10;
short_stem_height = 2;
long_stem_height = 5;
stem_diameter = 2;
groove_radius = disk_thick / 3;
addabit = 0.0625; // provide overlap to avoid z-offset
abitmore = 2; // ensure overlap for difference operations

module solids(){
    cylinder(h = disk_thick, d = disk_diameter); // main disk
    translate([0, 0, -short_stem_height + addabit]) // move short stem below disk
    cylinder(h = short_stem_height + addabit, d = stem_diameter); // short stem
    translate([0, 0, disk_thick - addabit]) // move long stem above disk
    cylinder(h = long_stem_height + addabit, d = stem_diameter);
}
module inthegroove(){
    rotate_extrude(convexity = 10)
    translate([disk_diameter / 2, 0, 0])
    circle(r = groove_radius);
}
module holes(){
    cylinder(h = disk_thick + short_stem_height + long_stem_height + abitmore, d = axle_hole);
    translate([0, 0, disk_diameter / 2 - short_stem_height + disk_thick / 2])
    inthegroove();
}
difference(){
    solids();
    translate([0, 0, -short_stem_height - abitmore / 2])
    holes();
}

idler.jpg

If you do as I suggest and research beginning 3D printing, you'll discover the concept of supports. In this specific model, it cannot be printed without supports under the disk. This is a mild case, in that the supports will be easily removed and the surface of the disk will be easily cleaned. Some supports are extremely challenging to remove due to the required location and also equally difficult to clean. There are design considerations that can minimize this problem, but I have not incorporated them into this model, as I believe this is still a non-printable design under most circumstances.

If you are determined to print this model, check out Shapeways and select the SLS nylon option to see what restrictions are part of the submission process. The extremely thin wall on the axle may be within their requirements; I do not know.

[hdtvjeff]

I shall heed your adviceMy nozzle diameter is .4The manufacturer had said PLA is as good as nylon but I'll take your wordHeated bed tooLots to learn, lotsI build High power multimedia Pcs from scratch, I should be able to manage thisJust have to expect the learning curveThank you for all your help,Jef

[fred_dot_u]

If someone tells you that PLA is as good as nylon, they aren't listening to you or asking you the right questions. PLA is a great hobbyist material, while nylon is better suited when one is creating engineering grade parts.

If you're programming in Scratch, OpenSCAD should be a breeze for you. (grin)

[hdtvjeff]

Going to give myself a crash course, I am a fast learner.Are there any inherent risk from the particles emitted from a 3d printer which can be hazardous? I'm going to set this up near my PC. No USB with this 3d printer; just an sd card slot to read your files.I appreciate your help, alotThank youJeff

[fred_dot_u]

For most printing, PLA especially, there's no risk. Some people will find the odors from ABS and ASA to be problematic.

For the idler project, consider that you can create a CAD type drawing and issue it to Shapeways or SendCutSend and have a part machined from delrin or nylon. Delrin is pretty strong stuff and machines quite well. It's important to get the measurements correct, though, as each iteration can be expensive.

That's one aspect of 3D printing; I can create as many models as needed to get a correct fit and it cost only pennies in filament, but oodles of hours.

[hdtvjeff]

I enjoy the feeling of doing it myself.I repair 1970's panasonic stereo cassette decks and wish to make substitute parts since these parts have not been available for 50 years.I dream of the day most metal parts can be replicated.Setting up the 3d printer soon.Just worried about the hot bed and my cat jumping on it !Again, thank you for your time and patience