Author Topic: 3D printer - cheap as chips  (Read 7203 times)

Online Jo

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Re: 3D printer - cheap as chips
« Reply #90 on: January 10, 2020, 09:31:48 PM »
how about the greatest thing since chocolate?

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Online crueby

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Re: 3D printer - cheap as chips
« Reply #91 on: January 10, 2020, 09:33:52 PM »
how about the greatest thing since chocolate?

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Since chocolate cookies!

Online ddmckee54

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Re: 3D printer - cheap as chips
« Reply #92 on: January 10, 2020, 09:44:52 PM »
There's a couple of problems that I see with tape.  Most of the stuff that's readily available is either going to have adhesive that will soften at elevated temperatures, or the tape itself will be relatively soft and easily damaged.

The bed material on my D6 is tough enough that they send a sharpened metal putty knife with the printer as a spatula for removing the part after printing.  I've been using the printer since last April and don't have any scratches on the mat yet.

I've looked into getting a replacement mat from Monoprice and using it on my I3, since they've got the same size print bed.  The replacement mat is only about USD $20.  The replacement instructions SOUND simple, heat the bed up to 100C, peal the old mat up with pliers, and stick the new mat down while the bed's still hot.  I guess when I do have to replace the mat it's going to be welding glove or oven mitt time.

Don

Offline zeeprogrammer

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Re: 3D printer - cheap as chips
« Reply #93 on: January 10, 2020, 10:54:17 PM »
I could have had the term 'dam' wrong. I've seen it used in this context before but can't seem to find it now. No matter.

I hadn't seen the use of a raft/skirt/brim before (or just don't recall it) and it seems to make sense to me for very small parts.

I still wonder about the calibration of the nozzle to the bed. It seems too close given the markings on the tape as well as some of the prints.

If I recall correctly, there should be a setting about the thickness of the 1st couple of layers. That can also come into play.

No doubt you know this...a glass top can help ensure flatness versus something that may warp. Even on my machine, it auto-levels but only at 4 corners. As far as I know, the middle of the bed could be lower or higher.

I assume the temperature sensor for the bed is in the middle. I have had issues where the corners of a large part may lift up as the part cools during subsequent layers.

Having the 3D printer is great. Great cost in printing time but way cheap and doesn't take a lot of looking after when making test parts or things for around the house.
For Christmas I printed out hooks to hang our stockings.

Crud kids were more interested in the contents of the stocking than the extraordinary way they were hung.  ;D

My first 3D printer was a kit. The time spent fiddling with it to get a good print was too much for me. I got a work-out-of-the-box system and am happy with it.

Re: Don's post about the sharp metal putty knife...My system came with one as well. It's surprising how hard, sometimes, it is to get the part off the bed.
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Online ddmckee54

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Re: 3D printer - cheap as chips
« Reply #94 on: January 13, 2020, 05:44:49 PM »
Zee:

One other thing that the skirt or brim is good for, is ensuring that the print head is fully primed and ready to immediately start printing the part.

I can't recall where I found it, but I read that the rule of thumb thickness for your 1st layer should be 1/2-3/4 of the diameter of your nozzle.  I've got a 0.4mm nozzle, so I try to stay in the 0.25mm-0.3mm range for my first layer thickness.  As long as I don't do something silly like trying to print on an area where I haven't applied the glue stick to the bed, this works for my machine - YMMV.

Don
« Last Edit: January 13, 2020, 05:49:59 PM by ddmckee54 »

Online Jo

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Re: 3D printer - cheap as chips
« Reply #95 on: January 14, 2020, 04:07:26 PM »
Having tried the Prat stick on the bed I now find that the plastic will not stick at all even with fresh prat stick applied. So, at vast expense, I have upgraded the bed with a piece of glass. This came from an old picture frame and is 2mm thick.

I initially did not get the gap between the printer head and the bed right and all it printed was a smear on the bed  :facepalm2: Once I realised the tick, tick noise was because it could not get the plastic out of the printing hossle I raised the head a bit more and we are off and printing again  :)

Jo
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Online Twizseven

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Re: 3D printer - cheap as chips
« Reply #96 on: January 14, 2020, 04:21:57 PM »
Jo,

Is there any way you can support your cables above the bed.  The way they are currently sat makes me think they are (or could be) dragging on the edge of the glass/bed and preventing the head moving cleanly around.

On my Prusa they are in woven cloth tube exitting the rear of the print head which can flex reasonably easily.

Colin

Online Jo

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Re: 3D printer - cheap as chips
« Reply #97 on: January 14, 2020, 04:41:08 PM »
I had been thinking about that Colin. I have not yet decided on how. The printer has moved since I first got it into its permanent home so things like supports can now be considered.

The piece of glass coming from a rimless frame has nicely smoothed edges. However this first piece had a crack in it which has gone right across the printing area   :Doh: But it is only a practice piece so I am not bothered  ;)

Jo
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Online ddmckee54

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Re: 3D printer - cheap as chips
« Reply #98 on: January 14, 2020, 05:10:14 PM »
Attached are the before and after pictures of my kit built I3 clone.  The before picture shows the rat's nest I had when I first built the printer.  The wiring was done following the kit instructions, using the kit supplied spiral wrap, and a lot of extra cable ties.

The after photo shows the cable chains that I printed, I found them on Thingiverse, and the other modifications I made to the printer.

Some people swear by cable chains, others just swear at them, I found them to be quite useful in this application.  My biggest problem was the support that was required for the cable chain to the print head.  Then I found an under-cabinet 12V LED strip, killed two birds with one stone.  I got the support for the cable chain and my work light for the print bed.

Something to keep in mind.
Don

Online Jo

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Re: 3D printer - cheap as chips
« Reply #99 on: January 14, 2020, 08:36:19 PM »
Comparing the bases of the latest items printed with those that had been printed on the blue tape it is clear that the glass is both producing a smoother surface and the PLA has joined together much better.  :)

Jo
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Offline Flyboy Jim

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Re: 3D printer - cheap as chips
« Reply #100 on: January 14, 2020, 09:05:10 PM »
Comparing the bases of the latest items printed with those that had been printed on the blue tape it is clear that the glass is both producing a smoother surface and the PLA has joined together much better.  :)

Jo

Nice hockey puck Jo.  :LittleDevil: What's next?

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Online Jo

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Re: 3D printer - cheap as chips
« Reply #101 on: January 14, 2020, 09:16:57 PM »
Nice hockey puck Jo.  :LittleDevil: What's next?

Those are floor/carpet protectors to go underneath the feet of my new dining table that was delivered earlier today  :)

A 3D printer is just another tool, I will not be printing toys or ornaments with it. So it will be used as required  ;)

Jo
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Online ddmckee54

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Re: 3D printer - cheap as chips
« Reply #102 on: January 14, 2020, 11:38:13 PM »
Jo:

From the look of the "hockey puck" on the left, your print head was too high.  I only see a few dull spots on that print, those spots were the only spots that print was actually adhering to the print bed.  The entire surface of the print should have that uniform dull texture, it's the texture of the tape.

From the look of your part printed on glass it also looks like you might be under-extruding on the first layer, or your filament width is set too high.  When printing on glass you're aiming for the entire surface of the part to be glass smooth.  It's not uncommon to have to over-extrude on the first layer, there's a setting in your slicing software where you can adjust this.  The same is true with the filament width, there's a setting for that.  I typically extrude at  about 105% on the first layer.  When I pull the part off the print bed I don't want to see any trace of the filament lines in the first layer - if possible.  I've got a 0.4mm nozzle and I've found that fixing my filament width at 0.3mm is a good compromise.  I'm not sure which slicer you are using, but the default setting in some of the slicing software will vary the filament width in relation to the layer thickness.  I know that Slic3r will so this, as the layer thickness goes down so will the filament thickness, and your perimeter wall thickness.

There's a highly technical 3D printing term, smoosh.  You want the filament that you are laying down on the first layer to be slightly smooshed as you print it.  You don't want it to smoosh too much though, that will at the very least cause the outer perimeter to print too wide - the dreaded "elephant's foot".  Or worst case it will make the plastic smoosh up around the nozzle causing ridges that the next layer will have to deal with.  Getting the first layer right is kind of like tap-dancing in a mine-field.  There are SOOOO many ways that you can screw up the first layer, but when you get it right it is SO worth it.

Don

Online Jo

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Re: 3D printer - cheap as chips
« Reply #103 on: January 15, 2020, 08:22:31 AM »
Thanks Don, there is a lot to learn here  :)

I am using Ultimaker Cura 4.4 as my "slicer" software. For those of you who are new to this: This software allows me to load one or more items and locate them on the printing bed, to slice i.e. calculate the printing path for each of the layers including automatically generating a honeycomb of plastic in the solid parts, and the actual printing which includes the ability to preheat before starting the combined heat/print. I have found that preheating very useful.

As for the printer's power usage, the 6 carpet protectors I printed yesterday took one hour each and saw my electricity usage go up by around 3 KW.

Jo
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Online Vixen

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Re: 3D printer - cheap as chips
« Reply #104 on: January 15, 2020, 11:36:19 AM »
As someone "who would never want to own one" and "would find no use for one"; I have been following this thread with unexpected interest. It certainly seems that with a bit of extra work, it is quite possible to make a 70 quid printer do something which could be useful (but I am still unsure what that something useful may be).

I am starting to think that 70  may be a cheep as chips way to find out. Besides it could be an incentive to get on and learn 3D CAD. I have been promising to do that for a couple of years but have still to make the start.

So a few simple questions:

a) Is it clean and smell free for use in the office or is it best in the workshop?
b) Where does the "slicer" software reside? In the printer or in the PC?
c) Does the printer need to be connected to the PC, or is it stand alone?

Mike
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