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BobinOK
12-12-2017, 03:51 AM
This is kinda a continuation of the thread on making fixtures using a 3D printer. Was thinking of useful parts I could make with my printer and having the need for a spacer for the 3 jaw chuck on my G0602 I went looking. Ran across this on Thingiverse.com
https://www.thingiverse.com/thing:281899

Thought it was a pretty slick idea and decided to download the file and make one. My lathe has a 5 inch chuck and the designer says he sized it for a 6 inch chuck. I opened it with Cura, scaled it down 80%, saved the G-code and waited the 6 hours it took to print. As anyone can imagine the important part of this fixture is how true one face is to the other. Right off the printer I measured the thickness and it's whiten the capabilities of my digital calipers all the way around and fits the chuck on my lathe perfectly. I printed it using PLA and my sample measured .605.

Guess other than pointing out a useful 3D printed fixture this proves the point that 3D printers are more than accurate enough to make fixtures for machining.

http://bbs.homeshopmachinist.net/attachment.php?attachmentid=2003&d=1513068504

gstprecision
12-12-2017, 04:14 AM
Very nice. It is on my list of print when I get a chance.

The biggest challenge I had with accuracy was shrinking and warping. I've been slowly getting better prints but sometimes on bigger parts I still get warpage of the base.

BobinOK
12-12-2017, 06:12 AM
I'm still learning and so far have only printed with PLA. I also have issues with large parts but chalked it up to my cheap printer and not yet doing several of the recommended modifications. In my case the issue is the first layer not sticking to the bed on an outer edge. From what I found on the net PLA is pretty forgiving of shrinkage and warping but ABS can and will shrink. The real test is going to be once I get the computer working with DesignSpark is to see how well a dimension is transferred from a drawing to the finished part. Decided on DesignSpark for my 3D drawings mainly because it's free, well supported and can import STL files.

This is the largest object I have made and had to start it twice, first time I had a big mess because one corner came up and the nozzle grabbed it. 2nd time I watched it and with the help of a pair of tweezers and flush cutting dykes I was able to get it past the corner that had lifted. Hoping when I get the rest of the mods I have stuff ordered for that problem will go away.

MrFluffy
12-12-2017, 07:00 AM
If you are using pla, hairspray on the bed occasionally will help it adhere and painters/masking tape over the bed although when I printed a lot of pla I had a unheated bed which this setup suited.. Also the model design and supports etc make a massive difference to printability. Some things I downloaded I could never quite print 100% sucessfully and everyone else fought them too, but others, load, slice, click go. If you do it right and have the first layer set right, you almost have to lever up the part afterwards. Also how unflat the bed is from the factory usually a eye opener, I probe a few points and self level but given the heated bed is made from aluminium, it isnt exactly stable in how it reacts each time so I run that routine at the start of a print anyway once the bed and nozzle is preheated to temperature so its done at final expansion and when everything has gone spang properly.
For abs, I use nothing on the bed, I have a heated bed with just a sheet of kapton covering the surface. Nowadays I almost always print in abs or nylon etc as I found pla weakens after 6-12 months of age. A lot of the early things I have made that were under medium stress broke as they became weaker and had to be reprinted + its useless for anything you want to leave in a vehicle/will come into contact with warm things unless you want a drooling blob instead of a cupholder in your motorhome when you come to use it. For stuff for the kids its ace though at first to deal with, abs gives off a lot of fumes etc that you have to deal with and I never managed to print it really sucessfully without a heated bed.
Dimensionally, depends on how big it is, tolerance your shooting for, the temperatures etc, you can always print it thicker and push the final layer thickness up in your slicer to allow you to take a skim off it in situ to true it up.

Dan Dubeau
12-12-2017, 09:23 AM
Nice job. Cool use of a 3d printer. I'm going to buy one in the new year after the Christmas wallet stops sizzling, just can't decide which one to get yet.

J Tiers
12-12-2017, 09:39 AM
Yowza.... those things take a lot longer than I figured. Six hours?

engineerd3d
12-12-2017, 10:05 AM
Yowza.... those things take a lot longer than I figured. Six hours?

Its always a balance of speed and quality.

For example, if the part can stand to be low res, then .3mm layer @100mm/s can be done. Would cut the print time a whole bunch. However if you want higher quality, then .1mm @30-40mm/s, sometimes you go for for something silly like .06mm @ 25mm/s.... Also printer type has allot to do with speed. CoreXY printers as well as Delta printers are faster than the old school H-Bot & prusa style printers. The nice thing about a 3d printer is that your time investment is in the design, the machine hours are in the range of 1-5$/hour. SO less than minimum wage.. LOL

MrFluffy
12-12-2017, 10:57 AM
You dont have to sit there watching it either, its not like proving a cnc milling/lathe program where you run through it with fingers on e-stop anxiously, it either adheres then does a few layers and you know its good, then you can just make sure it has enough filament on the spool or a rough idea when change time is due to complete the print, and you can be noodling around in the same sort of area doing something else.

I *used* to print lights out on my 3d printer in the office trusting it to just keep going and I think the longest print I did took 26 hours, but after a electrical fire from the heated bed controlling solid state relay exploding and reading about a few people that torched their houses doing the same while asleep, I'm a bit more cautious.

garyhlucas
12-12-2017, 12:05 PM
Those cheap chinese temperature controllers are why my 3d printing attachment for my cnc mill isn’t working yet. Got everything working and going to start my first print. The head stops extruding and I realize the controller has melted down! I repair the board and try again. I notice the heated bed is really hot. The 25 amp solid state relay has shorted on!

I almost have it going again. No more junk. DoMore PLC with real analog inputs reading thermocouples and real tunable PID loops. Driving real Crydom solid state relays that are heatsinked and oversized. My machine is enclosed. Maybe time for an extinguisher system in the enclosure.

engineerd3d
12-12-2017, 12:23 PM
Those cheap chinese temperature controllers are why my 3d printing attachment for my cnc mill isn’t working yet. Got everything working and going to start my first print. The head stops extruding and I realize the controller has melted down! I repair the board and try again. I notice the heated bed is really hot. The 25 amp solid state relay has shorted on!

I almost have it going again. No more junk. DoMore PLC with real analog inputs reading thermocouples and real tunable PID loops. Driving real Crydom solid state relays that are heatsinked and oversized. My machine is enclosed. Maybe time for an extinguisher system in the enclosure.

What kind of bed are you using? I am running a 24v bed at 28v. THat overdrives my bed quite a bit. No SS relay necesary just proper cooling on the mosfets. Now if your running 110v or 220v bed then I can see the need for SS relay. One more thing to note is that solid state relay's even from the big guys are not necesaryily fool proof. An inline properly rated thermal fuse would work wonders in your setup. Same kind as used on coffee machines. Usually cost 2-5$ and they work very well. THere are some that cut off at 150c and some that cut off at 125c, perfect for a heated bed. THose can also handle 10A continous or more in ac environments. Just my .02c.

Paul Alciatore
12-13-2017, 12:22 AM
I have also just purchased my first 3D printer, a Cetus. Here it is making my first 3D part, a pad to fit in the X channels that came with the printer. I wanted to test it with a known, good file, so I found the model on the web.

http://bbs.homeshopmachinist.net/attachment.php?attachmentid=1996&d=1512629543

It came out perfect on the first try.

http://bbs.homeshopmachinist.net/attachment.php?attachmentid=2011&d=1513142036

I used the default nozzle and settings and I was pleased with the finish on the part. The irregularities seem to show up more in the flash photo than in real life.

Cetus has a platform with a special coating and it seems to work well. This was printed with the PLA filament that came with the printer and it had no problems sticking to the un-heated surface. In fact, it was just a tad hard to get it off.

Paul Alciatore
12-13-2017, 12:28 AM
I was encouraged by that initial success so I wanted to make something practical. I had a problem with this TV remote. The battery compartment lid had broken latches.

http://bbs.homeshopmachinist.net/attachment.php?attachmentid=2010&d=1513141539

So I designed this with Fusion 360 as a learning experience.

http://bbs.homeshopmachinist.net/attachment.php?attachmentid=1933&d=1510638648

And I printed it.

http://bbs.homeshopmachinist.net/attachment.php?attachmentid=2009&d=1513141525

Not only did it print properly on the first try, but it also fit perfectly. I can't believe my luck.

http://bbs.homeshopmachinist.net/attachment.php?attachmentid=2008&d=1513141492

I guess I will be experiencing my learning curve later in the process, probably with a larger or more complicated part. I need to get back to Fusion 360 and work on some more ideas that I have.

THIS IS FUN!

dave_r
12-13-2017, 01:41 AM
Why not make new replacement latches?