New Anycubic Photon User (Page 1 of 2)

This test object is included on the USB stick that comes with the printer.  It does a good job demonstrating some of the capabilities of the Photon.  This was printed without supports.

-Kevin

I printed this rook from Thingiverse.  With the translucent resin, you can see the internal staircase.  This print is 19mm diameter base, and 28mm tall.

-Kevin

looks real nice!

I understand the Resin for these type printers has similar Hazards/toxic as Embalming fluid/formaldehyde which has been a big deal lately with construction materials in Homes as well. and when I was facility engineer for a large multi site  clinic one building was a funeral home and the embalming room cement floor still keeps breaking down and eating rubber tile flooring even years after digging down 10 feet removing contaminated soil from the chemical. so do be extreamly careful not to have similar issues.

I've downloaded ChiTuBox, but haven't looked at it yet.  It sounds like it has some advanced features.

How well did the fan arrangement reduce the resin fumes?  Are you able to use it in an enclosed room?

-Kevin

Thanks Carl; I had been wondering about the brands, since some people report their filament makes a smell, and the brand I use doesn't.

I've been using the Anycubic resin that came with the machine.  I have a different brand on order.  I'll try a few until I find one that is less malodorous, while still maintaining print quality.

I still have a lot to learn.

-Kevin

That's exactly what I had ordered from Amazon.  You're right: the smell is much less.

-Kevin

The z accuracy is sticking point in both this printer and the Wanhao D7. It has a lot to do with the Chinese screw. But it is adjustable as well in your settings depending on just how much access the manufacturer has allowed.

Another issue depends on your build surface. A cube built directly on the build plate will be much more accurate than one built on supports.

Although I don't have a Photon, I've been using my Form 1+ now for 3 years or so.  I'm now using ApplyLabWork resin exclusively.  I works really well in my printer and it's very reasonably priced.  They now have DLP resins as well, so you might want to give them a try.

Anyway, regarding size inacuracies, there could be 2 problems. 

1.  Resin absorbs alcohol, so if you leave a model in alcohol for a while during the cleanup phase, it will swell, and it will shrink back for a few days.  You should take your model an curit completely before measuring, then you will get a more accurate value.

2. Basically the image  being projected is not accurate, or there is some bleeding of light past the edges of the image.

You should print a test model that has cutout, for example something like a frame.  Measure the outside and the inside opening.  If your model is larger on the outside dimensions but smaller on the inside dimensions, then your issue is with either the optics or the resin being used.  It's the equivalent of over-extrusion on FDM, but it's not easily pinpointed on a resin printer, especially a DLP, or in the case of the Photon a Masked LCD printer. 

I've used photopaper (I mean developers photopaper, not inkjet photopaper) to calibrate my printer, and you can do the same.  Here is a 2d design you can use for testing.  I created a 3D extrusion out of it so you can print it.

http://www.soliforum.com/misc.php?actio … item=11124

The outside of the square is 60mm, the inside is 50mm.  The outside of the circle is 40mm, and the thickness is 1mm.  The crosshairs are .5mm.

Important:  Since you will be using photopaper which is light sensitive, take some precautions, like either very subdued, indirect light or even better, a red dark room bulb (I have Philips Hue in my room, and all I need to do is dial the color to a nice red).

Anyway, take some photopaper, put it pace down on the tray, put something on it like a book, to make sure it's flat against the bottom.  Remove the build platform, and tell the printer to print this model for about 10-20 layers.  This will expose the phototpaper.  Stop the printer, pull the paper out, and start measuring.  You should get some very defined lines/edges.  Since you already know what the measurements are supposed to be, you'll be able to tell how close the printer gets to them.

If you're working in a true dark room environment, you could even develop the image, if not, you should work fairly fast because the ambient light will start to darken the photopaper pretty quickly.

FWIW, I bought a pack of Kodak Polycontrast III RC B&W photopaper on eBay for like $12.00 for 50 sheets, and you'll probably end up using maybe 3-4 sheets depending on how quickly you can calibrate your printer, so don't feel the need to splurge on a large box, you probably won't need it.

Good luck.

I understand that there are no "optics" per se other than the optical clarity of the vat itself (FEP or PDMS or whatever it's using, and maybe any glass that's on top of the LCD panel itself (if any).

But, as I mentioned in item #2 above,  the test will show you whether or not there is light bleed around the edges, that can contribute to dimensional accuracy.  I'm sure that over exposure will probably affect that too.

Edit:
For those not familiar with how the 2 technologies work, on the Form 1+ or any other Laser based SLA printer, the optics, or optical path, consists of the laser bouncing light through a bunch of mirrors, and up through bottom of the vat onto the resin.  So the dimensional accuracy is usually determined by the path taken by the laser as it draws the image.  That's governed by stepper/galvo controller, which is responsible for deflecting the laser beam.

On the LCD type the image is projected as a negative mask, where the light passes through the LCD panel and exposes the entire layer image in one shot.  Assuming the slicer software is properly calibrated, the exposed layer should be perfect, dimensionally.  The question is how accurate is the resulting image that the slicer produced, and how good is the LCD panel at producing a nearly perfectly opaque mask.  If the edges are not truly opaque, then light bleed will occur and affect the resin exposure, hence dimensional accuracy.

I use NanoDLP to control my D7. This screenshot is of the settings that control my Z accuracy.

On NanoDLP it is black and white. You can turn AA on and off but all that does is rounds out the sharp corners on the square pixels and causes a loss of horizontal resolution.  Most users do not have it turned on as it does cause a sharp loss in resolution. The issue here with the OP is not horizontal however.

It is the accuracy of his Z axis and that is controlled the same way it is controlled on an FDM machine but you are dealing with pulses versus steps since the movement is much smaller. So his issue is most likely mechanical as it has been for hundreds of others using this DUV technology.

Why do people have to use percent and inches in this hobby? The machines deal with hard cold numbers and mm. Stop converting and post the printed size versus model size. It makes things much easier. If your model is 20mm then your print is 20.6mm then say that.

Part of the problem I use NanoDLP which gives you far more access to the machines display and axis settings. I can even change the color of my mask if needed to possibly control some bleed. But if the option is available for the OP I would advise turning AA off if it is not.

I would also lower the cure time to the lowest possible.

Let your oven do all the curing. The printer is just supposed to get the resin firm enough to remove and handle. In the oven there is no resin the at can be added so there is no issue with bleed. In your printer the longer you cure the more surrounding resin there is exposed to light and added to your print. You also want to make sure the resolution on your screen is set correctly for the proper pitch and size of the finished model.

On NanoDLP I can remove the resin vat and turn on the mask and light. This allows me to actually see and measure that layers width to confirm dimensions that way. If they then vary I know it is cure time and bleed.

And for the record unlike the Lasers, the light from the UV array is the same wavelength as blacklight so it is not that harmful to the eyes. Just don't stare directly into it as it is bright.  Just use calipers and measure from and measure from the side while being careful not to scratch the LCD. You can also put a piece of paper over the LCD and this will even simulate light bleed so you can see just how much could happen.