Practical 3D Printing: Slicing

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Slicing

07.39

00:00	In this module we'll return to the velocity stacks that we looked at in CAD and complete the CAM work with our slicing software to prepare the parts for printing.
00:09	If you need a refresher on these parts, head back to the CAD module at the start of this section.
00:15	For this example we're going to be working with Chittu Box Basic as it's a very commonly used SLA slicer that's recommended by Aligoo for use with its Saturn 4 Ultra printer, which is what we're going to be using to print these parts.
00:29	The basic version is also free to download and use.
00:33	Before we bring our model into the software, let's assume we're starting from scratch and get a few things set up.
00:39	With the program installed and open, we can see the workspace is what we'd expect from most CAD or CAM software.
00:47	First we need to add our machine using the plus button at the bottom of the screen, or we may be prompted to do this as we don't have any machine loaded yet.
00:56	From here we can select our printer from the list, in our case this will be the Aligoo Saturn 4 Ultra.
01:03	We really shouldn't need to change any of the default settings from here, but if you're familiar with them for your machine, then it can be worth having a skim through and a double check.
01:13	We can also leave the resin and print settings alone for now as these will be applied in a moment.
01:19	After applying these settings we can then use Chittu Box's resin alliance feature.
01:24	This is essentially a library of most of the resins on the market.
01:28	For our project we're going to find Frozen's high temperature resin called TR300 and then click the application button.
01:35	We won't jump to the configurations from here, I'll show you how to find that the manual way.
01:41	Back in the workspace we want to navigate to the slice settings area.
01:45	From here we can choose our resin profile and review the settings under the resin and print tabs, ensuring they match the resin supplier's recommendations.
01:55	The exposure time is 1.7 seconds which we'll leave as is since our previous XP2 validation matrix returned good results for this value.
02:05	Check back to the calibration module if you're hazy on these details.
02:09	Notice how there will be 6 bottom layers that will be overexposed at 30 seconds.
02:14	We'll leave these defaults and the layer height at 0.05mm to keep things simple as these values should be suitable anyway.
02:23	Had our resin not been on this list, for example if we'd mixed multiple resins together, then we can come to these slice settings and manually fill them out from the supplier's recommended values or from what we've found works well from our own experimentation.
02:37	If we're happy with these values it's just a matter of clicking apply and we'll once again shift back to the workspace where we're now ready to bring in our model.
02:46	Just like with our FDM printed parts, we can either export mesh or step files and then upload these to our slicer, or alternatively in Fusion we have the ability to send a model directly between programs.
02:58	Back in Fusion this is done from the utilities toolbar under the make tab, then we use the 3D print function.
03:05	In the popup we select print utility as the preparation type and then navigate to the slicer program we want to use.
03:12	The format can remain an STL binary and the unit type as millimetre as this is what we've modelled the part with and we want everything to remain to the same scale.
03:22	With the model in the workspace, the first thing to consider is the print orientation.
03:27	And again if you're unsure of any details here, check back to the print orientation and supports module in the SLA fundamentals section.
03:35	As we know SLA prints aren't as prone to layer to layer adhesion issues and the mechanical properties are mostly equal in each direction.
03:44	So, the choice in orientation mostly comes down to the surface and print quality based on how the layers interact with the release film and where the supports will contact the part.
03:54	For an FDM print of the velocity stack we'd almost always have the flange base on the print bed.
04:00	However, if we do that with SLA, we'll create a big suction cup on the release film that will cause excessive release forces, potentially pulling the part off the build plate.
04:11	Lifting the part off the build plate slightly using the move tool and using support underneath will help to avoid this issue.
04:18	This orientation actually works fairly well for this part as the cross sectional area of the part stays relatively consistent throughout the print and the supports are minimised.
04:28	On that topic, if we navigate to the supports tab, we can automatically generate light, medium or heavy supports, modify their settings and delete or add our own supports as well.
04:39	Again, we'll keep the default settings here to keep things simple and we'll generate some light supports to see the outcome.
04:45	In this orientation, contact points of the support are minimal and due to the shape of the part, they'll mostly be on the underside surface which won't be visible.
04:55	The base of the flange is the only real concern as we want this to be as smooth and as flat as possible, however it also won't be visible so we'll just be able to sand it flat.
05:05	If we use the rotate tool to lean the part over more into a more conventional orientation for SLA printing, we'd actually get more support witness marks on critical surfaces.
05:16	So, with that in mind, we'll print the part in the vertical orientation but slightly raised off the build platform.
05:23	Moving on, we don't want to use the scale or mirror tools for these parts but we can drop in a second velocity stack and arrange them on the build plate to print two at once and save time.
05:34	We can see the estimated printing time on the screen only really changes with the build height or more accurately the number of layers that aren't affected by how many of the parts we have on the build plate.
05:46	We also have no need for the hollow, dig hole or repair tools in this case simply due to the geometry of the part.
05:53	However, as a demonstration, if we do hollow out the part, we can set the wall thickness and infill parameters to whatever we desire.
06:00	Once hollowed, the slicer will detect a cavity.
06:03	So, we need to use the dig hole tool to fix this and again we have control over the parameters of this hole.
06:09	We'll undo this and make sure our supports are all in place and that's all there really is to it.
06:15	So, from here it's just a matter of clicking slice before viewing the results.
06:19	Just like our FDM slicing software, we can drag the slider on the side to view the cross section of each layer.
06:26	We can see that the area of each cross section stays relatively consistent and we can use the island detection tool which for this example comes back all clear so we really have no concerns.
06:38	If we're happy with the results, we can save this file to a USB drive and transfer it to the printer or alternatively with WiFi compatible printers like ours, we can use network sending.
06:49	A second piece of software called Chitu Manager is required for this and all we need to do is connect to our printer through the network, hit send and then start the print.
06:59	We'll be covering what happens next in the following module so let's summarise what we've covered.
07:04	With our slicer installed we can set up our machine in the software and also select the resin we want to print, ensuring all the settings are as desired.
07:14	We can then open our model in the slicer and decide on the ideal print orientation, considering how this affects the print quality and the support structures.
07:22	Other tools in the slicing software may allow us to hollow out the part or add specific SLA 3D printing features.
07:30	Then it's just a matter of slicing and sending it to our printer ready for the printing process.