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Hi there

 

post-14192-0-83175600-1547871451.jpg post-14192-0-49048800-1547871535.jpg
 

I bought a Peopoly Moai a while back and have spent some time getting to know it. The Moai is a resin based SLA printer which can make models at least as good as Shapeways FUD. They can be found at https://peopoly.net/ , and their pretty active forum is at https://forum.peopoly.net/ . They also have an active Facebook group.

 

I'm nowhere near proficient yet, but I do have some sort of process together.

  1. Make the model -> export to stl files - Blender
  2. run through the repair software - Microsoft 3D Builder
  3. hollow & create supports -> slice -> create gcode - Asura (uses Cura as the slicer)
  4. Format SD card and copy the file onto it - Tuxera SD Card Formatter
  5. warm printer -> print ->clean ->remove supports

 

And these are some of the files I've made and printed so far.

 

post-14192-0-51340300-1547011704_thumb.jpeg
post-14192-0-48723300-1545557755_thumb.jpeg
post-14192-0-77943500-1536348255_thumb.jpg

 

Andy Y has been kind enough to allow the upload of stl files, so I'm going to put some up on here as I go along.

Edited by JCL
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Just one to start things off, GCR Barnum 10' 6" bogie sides. The file is 4mm scale, but obviously can be scaled. The file has two parts.

 

post-14192-0-14694900-1547880114.jpg
 
post-14192-0-86426000-1534915961_thumb.jpg

 

The STL upload isn't quite ready yet, so I'll put the file up on here as soon as I'm able to. In the meantime it's at https://www.thingiverse.com/thing:3062866.

It's ok to use it if you think it's good enough, but please don't use it commercially.

Edited by JCL
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The resin looks very expensive. How much of it do you need?

 

...R

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Great to see another of your 'tutorial' threads, JCL.  I you are able to upload some simple STL files, it would be interesting to compare results from different printer types.

 

Your support structure for the locomotive is interesting - I assume the model is too long to fit flat on the bed.  My own print-bed is a similar size, so this is a technique I shall look into.

 

Mike

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Hi Robin, I don't know how much it is in the UK, but here in Canada it's about $60 for a 500ml bottle. I'm finding that I'm getting quite a lot out of it. I did some tests a while back by weighing the vat that holds the resin before and after a print and found that, taking into account the electricity costs (this was before I heated the resin before starting) the wagon was costing about a pound to print. I'll do another test soon as I've the loco body to redo

 

Mike, thanks for that. The stl upload is with Andy at the moment, but he's not got a problem with us uploading in principle once it's sorted out. There are a few reasons for putting the model on a diagonal. One is because of suction forces. The vat that holds the resin has a layer of Polydimethylsiloxane (PDMS) on it, which is a type of clear silicone. The build plate is lowered into the vat of resin and then the laser 'draws' a layer of the design. Once that layer is complete, the vat tilts to separate the layer from the PDMS. The build plate then rises by the amount specified in the model file. The larger the surface area that is being peeled, the greater the suction forces that are exerted on the PDMS and the higher the chance that it will tear. When that happens you either have to buy a new vat or learn how to replace the PDMS layer yourself. By putting the model at an angle, you are reducing the surface area that is being created by each layer. It does also obviously help for those occasions when the model is longer than the build plate is wide. :) Using this I've calculated that I could get a GNR 6 wheel coach in there if I was brave enough.

 

To give you an illustration of this, 'Practical Printing' has created a series of Youtube videos that go from unboxing and setting up the Moai though to printing and finishing. Below is the video that shows the Moai printing a model. Go to 3:10 to see the printer actually printing (at high speed, the print takes 20 minutes in realtime). The ring he prints is a standard calibration model for the Moai (and probably others) and is used to determine how strong the laser needs to be. If the laser is too powerful, then the tiny holes in the ring will be closed up, if it's not powerful enough, then the ring and supports won't be properly formed.

 

 

You're right, a lot of people have gone for the Photon and are really pleased with it (have a look at the Sparkshot thread), and I know the Wanhao D7 is pretty comparable, so it will be interesting to see how we all get on with the different printer types.

Edited by JCL
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Hi Robin, I don't know how much it is in the UK, but here in Canada it's about $60 for a 500ml bottle. I'm finding that I'm getting quite a lot out of it. I did some tests a while back by weighing the vat that holds the resin

Thanks. Can you say how much resin needs to go in the vat to start things off? I presume it's more than 500ml.

 

Or is the initial vat full of resin included in the printer price?

 

...R

Edited by Robin2

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Hi Robin, I don't know how much it is in the UK, but here in Canada it's about $60 for a 500ml bottle. I'm finding that I'm getting quite a lot out of it. I did some tests a while back by weighing the vat that holds the resin before and after a print and found that, taking into account the electricity costs (this was before I heated the resin before starting) the wagon was costing about a pound to print. I'll do another test soon as I've the loco body to redo

 

Mike, thanks for that. The stl upload is with Andy at the moment, but he's not got a problem with us uploading in principle once it's sorted out. There are a few reasons for putting the model on a diagonal. One is because of suction forces. The vat that holds the resin has a layer of Polydimethylsiloxane (PDMS) on it, which is a type of clear silicone. The build plate is lowered into the vat of resin and then the laser 'draws' a layer of the design. Once that layer is complete, the vat tilts to separate the layer from the PDMS. The build plate then rises by the amount specified in the model file. The larger the surface area that is being peeled, the greater the suction forces that are exerted on the PDMS and the higher the chance that it will tear. When that happens you either have to buy a new vat or learn how to replace the PDMS layer yourself. By putting the model at an angle, you are reducing the surface area that is being created by each layer. It does also obviously help for those occasions when the model is longer than the build plate is wide. :) Using this I've calculated that I could get a GNR 6 wheel coach in there if I was brave enough.

 

To give you an illustration of this, 'Practical Printing' has created a series of Youtube videos that go from unboxing and setting up the Moai though to printing and finishing. Below is the video that shows the Moai printing a model. Go to 3:10 to see the printer actually printing (at high speed, the print takes 20 minutes in realtime). The ring he prints is a standard calibration model for the Moai (and probably others) and is used to determine how strong the laser needs to be. If the laser is too powerful, then the tiny holes in the ring will be closed up, if it's not powerful enough, then the ring and supports won't be properly formed.

 

 

You're right, a lot of people have gone for the Photon and are really pleased with it (have a look at the Sparkshot thread), and I know the Wanhao D7 is pretty comparable, so it will be interesting to see how we all get on with the different printer types.

Looks very good indeed! And very generous of you to share the file for the GCR bogie and buffers. If you would like an stl file for a GNR six wheel carrriage to encourage your bravery, I would be very happy to send/share one!

I use imaterialise and Shapeways but have just bought my own printer, yet to actually turn it on though. Eagerly anticipating your future installments...

Mark

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Thanks. Can you say how much resin needs to go in the vat to start things off? I presume it's more than 500ml.

 

Or is the initial vat full of resin included in the printer price?

 

...R

 

Robin,

 

You definitely don't want to fill the resin tank since the plate assembly has to go down pretty well to the bottom of the tank for the early layers and that would displace quite a lot of resin out of a full resin tank.   On my Phrozen,  I put in about 5mm of resin to start and that seems to work well for a lot of the smaller items I am doing.   I top the tank up to 5mm when I think it's beginning to look a bit low.  I use the top of the plate as a measure - if the plate doesn't displace enough resin when doing the first layers to reach the back of the plate,  then I will top up for the next print.  I know that people doing large prints top up the tank during the print.

 

Jim.

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Hi Robin,

 

In my case, I was luckily enough to find someone locally (from Aberdeen no less) who sells them, so I received 500ml resin when I bought a litre of the stuff. As Jim says, you need to be careful not to overfill the vat. I can only talk about my machine, and it has a line etched into it that shows the resin safe limit. The worst thing I can do is have the resin come out of the vat and drip/spill ,down into the lower part of the machine that holds the laser and electronics.

 

Seeing as I've started this train of thought, I'll put down how I clean up a model.

 

The process can be messy if I'm not careful, and drips are a constant hazard. Also, the resin really isn't something you want to get on your hands or clothes. Interestingly, I've heard that they are attempting to formulate a resin that can be cleaned in water. The other things that I use when printing is:

  • some sort of plastic sheeting (or plastic carrier bags, etc) to keep the mess from spreading,
  • rubber gloves to keep the resin, etc, off my hands,
  • a plastic hotel key card or similar to scrape the residue off the top and sides of the build plate back into the vat,
  • a metal wallpaper style scraper to scrape the model off the build plate (it's better for me to get rid of the excess resin first),
  • Zuron cutters or similar flush diagonal cutters to cut off the supports. I do this slowly and carefully because it's easy to crack the resin if the supports are holding the model too stiffly,
  • tweezers to transfer the model backwards and forwards if it's not too big,
  • a container of 99% isopropyl alcohol into which I can start the cleaning process, I also use it to clean the build plate,
  • I use a paint brush to clean the nooks and crannies of the model. It also speeds up the cleaning. I wash the brush in the alcohol before putting it to one side,
  • a container of water - which helps with the cleaning. I alternate between this and the alcohol a few times,
  • kitchen towels to clean up any drips or spills and to clean the scrapers,
  • a UV light of some sort, or the sun, to cure the cleaned up model. The curing is a lot faster if the model is in a clear plastic container with the UV light shining into it.
I know the model is clean when it's no longer sticky, and I'll know it's cured properly if it feels harder than when I took it out of the machine and I can no longer scratch it with a finger-nail.

 

post-14192-0-51364600-1547973959_thumb.jpeg

 

The water and alcohol end up being a solution of the resin which gets thicker and thicker. The solution will also pick up bits of cured resin which may stick to the model, also although you can reuse the resin a few times, if it gets too concentrated it will stop working. The spent solution can't be flushed down the plumbing or thrown outside, so you need to remove the liquid from it. This can either be done in the sun over a few hot days (not great, obviously), or in kaolin clay style kitty litter.

 

Going back to the video series from Hawaii, this is how the Practical Printer feller does it.

 

https://www.youtube.com/watch?v=TG97XRVD51Q

 

Hi Mark, that would be brilliant, I'm heading into Victoria on Tuesday to meet a man in a carpark where we will be transferring two bottles of resin from the boot of his car to the boot of my car. I can't guarantee in any way that it'll come out properly, mainly because support creation is as much an art as it is a science and I'm still learning it.

 

It's worth waiting until you have an afternoon or something to spare when you do turn on your machine so that you can give yourself some time to really get into it. If it's like mine, there is a learning curve involved, so gather together your papers, etc, before you start. I'll send you a pm. :)

Edited by JCL
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You definitely don't want to fill the resin tank since the plate assembly has to go down pretty well to the bottom of the tank for the early layers and that would displace quite a lot of resin out of a full resin tank.

Thanks. However I'm still not getting any sense of how much resin you need to put into the tank.

I put in about 5mm of resin to start and that seems to work well for a lot of the smaller items I am doing

How much resin is needed to give you the 5mm depth?

 

And I presume that means the things you are printing cannot be more than 5mm thick.

 

 

Also based on what is in Reply #9 the whole management process seems to be very messy and time consuming compared to the extruder type of printer, though I do recognize that the ability to produce fine detail is much better.

 

...R

Edited by Robin2

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Thanks. However I'm still not getting any sense of how much resin you need to put into the tank.

How much resin is needed to give you the 5mm depth?

 

And I presume that means the things you are printing cannot be more than 5mm thick.

 

 

Also based on what is in Reply #9 the whole management process seems to be very messy and time consuming compared to the extruder type of printer, though I do recognize that the ability to produce fine detail is much better.

 

...R

 

Robin,

 

I could calculate it by taking the area of the tank multiplied by 5mm.  But it's quicker to say that I am about half way down my first 500g bottle having done a dozen or more prints in the last month or so.  I ordered another 500g bottle before Christmas thinking that I might run out soon after Christmas,  but I'm still on the first bottle. :-)   Admittedly most of my prints are relatively small but unless you are doing large thick-walled prints (or even large solid ones) then your resin usage is quite low.  The slicer program I use shows an estimate of the resin used.  I've just done a test with a Fox coach bogie side in S scale and the program assesses that 3.5g of resin will be used.  A lot of the larger files I have printed barely get more than a 10g assessment - and the low usage from my first 500g bottle of resin would support this.

 

I think you have to re-visit the theory behind these resin printers.   The printer lays down successive very thin layers upside down with the head rising by the layer height for each UV exposure - whether by laser or LED.   It is possible that I could print a 200mm high object on my printer starting off with 5mm of resin in the tank if that quantity of resin was sufficient to print the whole piece.   Having a reservoir of resin in the bottom of the resin tank is an efficient way of replenishing the resin required for the next layer to be exposed.

 

It is a bit messy but not too bad once you get set up.  You have to get rid of excess un-exposed resin at the end of the print or it will eventually set under available UV from daylight and affect the resolution and detail of your part.  I started off by dunking parts in bottles containing IPA as in the video above,  but I have now progressed onto using a cheap airbrush to spray IPA at the pieces to clean the excess resin out,  then just spray air to dry off the IPA on the part.  This has worked very well and is a good bit easier than dunking and brushing.  An ultrasonic cleaner might be even better but I would probably still need the airbrush to blow off the IPA.

 

Jim.

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Also based on what is in Reply #9 the whole management process seems to be very messy and time consuming compared to the extruder type of printer, though I do recognize that the ability to produce fine detail is much better.

 

 

 

It is also a lot messier and long winded than using a well thought out printer like a Form 2

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  It is possible that I could print a 200mm high object on my printer starting off with 5mm of resin in the tank if that quantity of resin was sufficient to print the whole piece.   Having a reservoir of resin in the bottom of the resin tank is an efficient way of replenishing the resin required for the next layer to be exposed.

 

It should also be possible to replenish the resin in the tank during a print.

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It is also a lot messier and long winded than using a well thought out printer like a Form 2

 

 

Just taking a quick look and the Form 2 is twice the price.

 

https://formlabs.com/store/uk/form-2/buy-printer/. £3,300-5,300

 

https://www.imakr.com/dlpsla/2038-moai-sls-3d-printer.html £1,700

 

Is the lack of cleaning worth the extra outlay ?

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I could calculate it by taking the area of the tank multiplied by 5mm.  But it's quicker to say that I am about half way down my first 500g bottle having done a dozen or more prints in the last month or so. 

OK, that makes things a lot clearer. I had been assuming that to get started you would need to put 3 or 4 litres into the tank and then keep it topped up as it gets used.

 

Thanks.

 

...R

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Is the lack of cleaning worth the extra outlay ?

 

 

Perhaps you should have looked at the spec instead of just the price.

 

The Form 2 was designed for semi-production and so it is a somewhat more sophisticated machine. This how's in a number of areas:

 

  • It has wi-fi connectivity, together with ethernet and USB, so not only is there no messing with SD cards, but the printer will report back when the print has finished and any errors that need dealing with.
  • It has a cartridge system that dispenses resin into the tank, so there is no messing about with bottles of resin.
  • The printer, software and resins are an integrated system, so the 'just work' together without the need to fiddle with lots of arcane settings.

To start a print all I have to do is choose a print from the files already uploaded to the printer and press a button. When a print is finished I take off the build platform, dump the prints into IPA and start another print.

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Perhaps you should have looked at the spec instead of just the price.

 

 

The price usually indicates a higher spec, and being at work I didn't spend too long looking.  

 

Higher spec or not, £3,000+ for a home machine is going to be beyond a lot of budgets and my reading of the thread was that it was intended for the 'Average Modeller' looking to experiment with 3D printing,  rather than getting into 'semi production' so is the extra outlay worthwhile?

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It is also a lot messier and long winded than using a well thought out printer like a Form 2

Hi Dave and Bill, I think it’s like the WSF and FUD conversation, it depends on what you’re using it for and how much money you have to invest in a 3D printer. If I was a manufacturer, or a heavy user, then it would make sense to pay for the convenience, but as it stands, that’s not the position I’m in. I am also enjoying tinkering with it, which is unusual for me nowadays.

 

Looking at prices (in US$, less tax, first one I found), the Wanhao D7 is ~$500, the Phrozen is ~$800, mine was $1,300 and the Form 2 is $2,200+. Mine is marketed as a budget model, but obviously that depends on the budget people have available. I think that, if I’d known about the Phrozen I’d have looked into that one, but it somehow passed me by, and I didn’t go for the D7 because I kept reading about problems people were having. Overall, I’m really happy with the printer.

 

One thing, it is possible to replenish the resin in the tank, but again, it’s a case of pouring it in, rather than changing a cartridge.

 

On the messiness, as with all things, as I get better at using it, I’ve managed to minimize this with my process in the last few weeks to the point that there’s hardly any at all. I still wouldn’t dare process on the bare dining room table though. :)

 

I’m trying to make this an informative thread for people to dip into, and I’ve mentioned before I don’t have all, or even the majority of the answers as I’ve only been at this a couple of months, so I’m really happy for other people to chip in with their experiences. It’d be interesting to know what you do with regards to post processing with the Form 2 Bill, and to anyone else with a different model.

 

Hi Jim, I’d not thought about, or read about using an airbrush for cleaning. The chemicals aren’t great, can you tell us about your setup?

 

Here’s a bonus pro tip for you. Before setting off a 2 hour print, make sure you put the vat back in the machine...

Edited by JCL
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Hi Jim, I’d not thought about, or read about using an airbrush for cleaning. The chemicals aren’t great, can you tell us about your setup?

 

Here’s a bonus pro tip for you. Before setting off a 2 hour print, make sure you put the vat back in the machine...

 

I first picked the idea up on the Facebook forums but I also noted that the instructions on the Phrozen resin bottle states "Clean with alcohol spray with airgun".  I've got a cheap double action airbrush so I use it at 20psi and it seems to do the job very well.   I find that it's easiest to do the work with the airbrush while the parts are still stuck to the plate - much easier to hold and keep the fingers out of the way of the spray.    Then I get the parts off the plate and off the supports and at the moment I dunk them in a Kilner jar filled with IPA,  just to be sure,  and then retrieve them and use the air spray as a blow dry.   I think the dunking is overkill and I'll probably miss that out in future.   The Kilner jars came from the local superstore and are large enough to get my hand in easily and they have the clip top lids which open and close easily with a liquid and airtight seal.

 

My UV curing is done in a white plastic bin from the same local superstore with the five metre strip of UV LEDs stuck round the inside.

 

My bonus tip is take off the cover on the top of the resin tank before starting to print. :-)

Edited by flubrush
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I was talking to a couple of people the other day (you know who you are), and we thought we'd have a look so see how the printer works with larger items and suggested a model. The Moai is mostly used by people doing figurines and cosplay items, and is supposedly less good at straight sided items. Proper calibration helps with this, and the software they are writing called Asura. This now allows us to create a simple calibration table that will negate any problems due to the type of technology used to create the print.

 

Anyroadup, after looking up some tutorials on Youtube, I put together the body for the NER petrol inspection railcar as a test.

 

post-14192-0-76980700-1548279483_thumb.jpg

 

The drawing in Blender

 

post-14192-0-86935500-1548280525.jpg

 

As I'm not printing the base and the roof today, I decided to print the vehicle 'flat', that is not on an angle like the wagon above. I printed them with 'coarse' settings of 100um - the settings go 100, 80,60,40,20um. You can see from the image I added a couple of cone ended spacers to the body to make sure that everything stays square.

 

post-14192-0-86267800-1548281041.jpg

 

On the build plate. When being printed, the build plate is the other way up and the model is printed upside down. In the first photo the model has a film of uncured resin on it, so it looks a bit odd. This is the model again after the repair check and after the supports have been added in Asura. It's now ready to print.

 

With this type of printer, any parallax errors get bigger as you get closer to the edge of the build plate, so even though the build plate is 130mm2, unless it's calibrated, it's best not to go right up to the plate edges. The print of my model is 1.5mm shorter and .3mm thinner than the drawing, so I've a bit of calibrating work to do. That said, the walls are vertical like they should be, so it looks like printing it in this orientation has worked.

 

post-14192-0-91179900-1548280167.jpg

 

These are photos taken after the model has been cleaned, the supports removed, and the nubs filed slightly. I made sure that the base of the model stayed true by rubbing on a piece of 600 grit sandpaper.

 

post-14192-0-78335500-1548280180.jpg

 

post-14192-0-89673400-1548280197.jpg

 

Here they are with some primer and nasty raking light.

 

post-14192-0-02766000-1548281698.jpg

 

post-14192-0-10336800-1548281718.jpg

 

 

I've uploaded the walls to Thingiverse, and as soon as I've done the roof I'll upload that too.

https://www.thingiverse.com/thing:3376888

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 The Moai is mostly used by people doing figurines and cosplay items

 

 

I don't remember you mentioning that before...

 

Looks good, you ought to motorise that.

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I don't remember you mentioning that before...

 

I don't think I have. The official Facebook group is mostly people making sci-fi and fantasy figures.I think that there are only a couple of us doing what I'm doing here. It's a bit like the Silhouette at the beginning of that thread I set up. I remember then that the only site that had any usable information was Belgium based and in French

 

 

 

Looks good, you ought to motorise that.

 

I've been asking my chassis building friend, but he's reluctant...

 

Edited to say, I can't believe this was my 3000th post.

Edited by JCL

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A quick update, this is the body with a coat of paint. When I print it again, I'll change the supports so that there are fewer supports inside the windows, do what Mike T suggested, which is to round off the beading, do some beading width adjustments, and bring the vents out a bit more. As a first go, it looks ok though.

 

Next time I print it, I'll weigh it as soon as it comes out of the printer, that way I'll be able to tell you how much resin it actually uses (and the cost of the resin).

 

Interestingly, on the vertical panelling next to the central door you can see a slight marking which is more obvious in the photos above showing the model in grey primer. This seems to be the effect of the supports on the side. Next time I'll leave them out and see what happens.

 

post-14192-0-70274300-1548309620.jpg

 

post-14192-0-23129000-1548309641.jpg

 

cheers

 

Jason

Edited by JCL
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Hi Bill

 

I added the horizontal braces manually using a cylinder and a cone on each end so they are completely adjustable. I think you originally gave me the idea last year when I had problems with a Shapeways print of the GNR G1. It worked a treat then, but not quite so much with this one.

 

The next one I print won't have the horizontal braces as I may have been a bit over zealous. it'll be good to see what the printer is capable of.

 

Edited to add:

 

I've just checked my Asura software, and it's possible to change the diameter of the tips of the automatic supports holding the model to the base. At the moment they're 1mm, but this can be reduced. It's also possible to do this in the other software that I use sometimes, B9 Creator.

Edited by JCL

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