Tag: 3D printing

Almost everyone who gets a 3D printer thinks about two or more extruders to create multi color prints. The Zonestasr P802QR2 is a simple to build kit that has two extruders that feed into two nozzles. It consists of a full metal 1 ½ mm thick. It has a 220X220mm bed and 240mm Z, although the Z only has 185mm actual usage. The placement of the LCD catches the PTFE tubes that guide the filament into the hot ends. I’m going to bend it 180 deg up to keep it from catching and I think it will look better. That or I’ll cut it off and design and print my own display holder in 3D computer aided design. Which is my favorite thing about 3D printing.

I’m not a fan of the frame style. Like the Anet A8 it has little support from wobbling side to side. But you can easily print supports which you can find on the Thingiverse website. Although many complain online about the 3D printed printer parts, I’m fine with them. Sure, some parts don’t get very accurate but the great thing about these things is they can self- heal by making new parts. The Zonestar P802QR2 also comes with an auto level sensor which is a nice feature.

Unboxing

Like most DIY kits, the Zonestar P80QR2 has a lot of parts. The only part assembled for you is the Extruder. That is because the dual hot ends are very hard to get even. They did a good job assembling mine. The parts were separated by foam to keep the parts from damage during shipping. None of my parts came broken or damaged.

SD Card

The SD card comes with all the documentation for all of Zonestars 3D printers. It makes sense but I believe some users may choose the wrong model because they are very close in name. It also comes with test print files. Overall, it was well done and very well organized.

Assembly

Assembling this printer is about the same as every other kit out there. Kits like these are fun to build, at least for me it is. I was busy at the time so I built it over a couple of days. The guides are very easy to follow and it should only take 3-4 hours to build. Having dual nozzles add a bit of complexity. Nowadays, you get kit printers that are mostly completed at the factory leaving you to put 2 to 4 pieces together.

Software

The recommended Repetier-Host software on the SD card is not my favorite program to use with printers. The software just “hosts” a slicer engine. The slicer is the program that slices the 3D object into layers, then turns it into instructions the printer can understand. If you need a free program then I would recommend Slic3r or Cura, but if you can afford it I would recommend Simplify3D.

Multiple Extruders

This printer has two hot ends and two nozzles. Multi extruder machines come in two ways. The first being each extruder having its own nozzle. The second is each extruder feeds into a splitter and out ones nozzle. The multiple nozzles type has more downsides then the single. For instance, it takes more room so you have to enlarge the printer to get each extruder to reach all of the bed. Another and the most important is leveling the bed. When you have two or more nozzles, your bed and X axis have to be 100% parallel. On top of that the nozzle tips have to be 100% even. When the layer thickness is 0.1mm and some even 0.05 then you can imagine how even they need to be.

The reason is if one is off by more than 0.1, then it will drag one of the nozzles across the top of you prints leaving ugly marks. Another problem is that if you are printing one color and the second nozzle is not hot, it can catch your prints and knock it off the bed ruining your print. It can also happen if the second is heated also. Just heated, there’s a chance it will melt it and cut through the print. Plus the supports that help your print overhangs get knocked down easy if the second nozzle is lower then the main nozzle. So you are better off having the second nozzle a bit higher rather than lower. Having two nozzles has oozing problems. While one is printing the second one oozes filament from the nozzle being hot. Therefore when you start printing with the second nozzle the tip is empty leaving holes in your print. Not to mention the oozing filament get all over your print.

The many extruders to one nozzle type gets rid of the oozing and leveling problems but is not without its own problems. For instance, when one filament is retracted back it leaves a small thin string of filament. So when the next filament get inserted it sometimes jams from it not fitting in the tube with the string left behind. Also, the nozzle being filled with melted filament from the last color will bleed that colour into the print where it shouldn’t be. To counter that, the slicers now have a purge block where it prints the block between color changes so the bleed goes into the block and not the print. The problem with that is the block is a big waste and sometimes is more plastic then the print itself.

It is for that reason multi color printers are not as popular as they should be. This printer comes in three models. One with one extruder. This one with two extruders and two nozzles. And the third being two extruders into one nozzle. Oh, and one nozzle gives you the big bonus of mixing the two colors.

This is what it looks like if your bed and nozzles are not 100% level. I let this go to show you what happens when it is not level.

Calibration and Printing

PLA

PLA is the easiest of all filaments to print with. It sticks to the bed well, it doesn’t shrink and warp as easy as other filaments. Most use PLA unless they need to print something that needs special properties such as UV tolerance or extra strength.

My first few prints were to calibrate the two nozzles. To calibrate the slicer and printer needs to know the distance to the second nozzle on both the X and Y axis.

The first print I did was with the two calibration blocks that come on the SD card. There is a dual color print wizard in simplify3D. It’s a bit buggy because sometimes I open the app and the dual processes disappeared. The first one had a large layer shift. The second one printed ok and showed an x axis offset.

The Block did give me a proper picture so I printed this target looking test print. (Not on the SD Card)

After setting the offset in the firmware through the menu, I printed the two-color globe. I didn’t have enough blue so I used pink for my daughter. As you can see the ooze from the nozzle not in use takes its toll on the print.

After some light sanding I got most of the pieces sticking out but it didn’t come out all that great.

Next, I decided to try one filament just to see how the printer prints. I printed the 20mm XYZ cube and it printed pretty well.

In one of my reviews I printed the Star Wars clock from Thingiverse. I’ve seen this dual color Batman once and had to try it. It was a tough print and the two colors do not stick together as well as it should have. Also the second nozzles leave marks on the top layer.

The last PLA print was a simple single color minion. The print quality while not great is acceptable. The thing about these printers is you can always improve them if you have the patience.

Flexible Filament (TPU)

Flexible filaments are very cool. I usually print quishi toys for the kids. The problem with the filament being so flexible is that it can spool around the feeder gear. The Zonestar P802QR2 has extruders with a small enough gap, but because it’s so small I had trouble loading the filament. I had other ones laying around so I installed them.

One plus side to having separate nozzles is that you can mix types of filaments. That is great if you want to print something like a 3D printed hand to have hard fingers (PLA) and flexible joints. I tried but failed twice and moved on. I will give it another try when I have some time.

PETG

PETG is a tougher alternative to PLA and is widely used. The first print failed because the second nozzle kept ripping the supports down so I stopped it. Then I printed the Kratos bust that didn’t need much support. This print came out nice and you can barely see the layer lines on some parts. PETG is stringy and hard to get the retraction settings correct.

PROS

• Dual hotends
• Extra stepper driver. This lets you add another extruder.
• Metal frame.
• Auto level sensor
• Prints well
• Price

CONS

• Dual nozzles
• Frame design is flimsy in the X axis.
• 3D printed parts can be inaccurate.

PRINT QUALITY: 7/10

Good start and I give it 7 with room to grow.

BUILD QUALITY: 7/10

Metal frame is better than the cheaper acrylic printers on the market.

USER INTERFACE & NAVIGATION: 4/10

I’m no fan of the 5-button LCD panels. Especially since the full graphics displays are so cheap today.

VALUE FOR MONEY: 6/10 

The Zonestar PQ802 QR currently being sold at $250 isn’t too bad. There are cheap printers for sure. But this does have two extruders and a stop for a third. It even includes the third driver.

Conclusion

The Zonstar P802QR is an entry level printer for sure. And a dual color one at that. But I can’t in good conscience recommend a dual nozzle printer for any beginner.

If you really want a cheap printer with two or more colors, I would recommend the Zonestar M8R2 Colour mixing printer first. It uses one nozzle and you don’t have to be concerned about the nozzle ruining most of your prints. Most people who get these dual nozzle ones take the nozzle off the second one and use it as a single color printer. I’m going to be making the Y splitter and feed 2 or 3 into one tip.

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