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UHU vs. generic glue stick. Getting PLA to stick to the print bed.

Hey hey! Getting the first print layer of PLA to stick well to the print bed is a crucial part in determining the success/failure of your print. Without proper adhesion of the print to the print bed, the print can potentially warp around the corners for large prints. The print can also pop off entirely in the midst of printing, leading to a mess if print is not stopped manually. A common way to the prep the print bed for PLA printing is to have a layer of blue painters' tape on the print bed. However, sometimes the print can adhere to the tape so well that you can damage the tape layer while trying to get the print off. And the tape is not cheap! (edit: 30sgd a roll)   Today, we experiment using 2 different brands of gluestick. UHU glue stic and a generic bookstore glue stick. The uhu gluestick costs 1.85sgd for a 8.2gram stick while the generic one cost 1.90sgd for a two-pack of 15g! The story goes like this. The reprap community found out that the gluestick contains a formulation of a polymer called PVA(polyvinyl alcohol) and/or PVP(polyvinylpyrrolidone). These two polymers are found to have good adhesive property with PLA (and maybe ABS. we have not try it). So, instead of using blue tape to prep the print bed, users have reported success using a thin layer of gluestick glue smeared onto the print bed. Users also found out that PVP formulation of gluestick works better (read: adhere better) than PVA formulation. The uhu gluestick did not specify what kind of polymer is used in it (so it could be PVA or PVP), but for the generic one, we can see that it is apparently PVP.   We first tried the uhu gluestick. A single smear to cover the print bed area is sufficient from users' reports. The print sticks quite well to the glass sheet with uhu gluestick smeared on it. Note that this is done using a cold bed with temperature of around 23 degrees C. Users have reported that it works better with a heated bed of 60 degrees C, but we want to try if we can save some electricity (: When the print is done, we could twist and pull the print off the glass bed with moderate amount of force. It feels like a tenth of force needed from pulling off prints from blue tape. The base of the print is only a tiny bit sticky, however, a good wipe with a moist cloth should clean the remnant glue off the print. The print bed continues to have a layer of smeared glue. It is reported that a layer can last 3-6 prints before requiring a clean up and reapplication of the glue. Next up, generic PVP-based gluestick. We tried to keep the bed at the same level (relative to the nozzle) for both cases. After the print is done, the force required to remove the print feels much larger than from the UHU gluestick case. It feels almost 3 times as much. If the UHU gluestick does well, then this cheaper generic brand does better! We think that it is because of the PVP formulation. (Then again, this could be a placebo effect. But we are sure that it takes a larger force to remove the print!) The image below shows the imprint left behind on the glass sheet by the print. It looks messy on the glass sheet (clean freaks stay away!), but the glue is almost invisible on the print itself. (:   We think that we will be using gluestic instead of blue tape more often now, as we find that blue tape sticks excessively. The gluesticks will probably last us for a loooooong time for many many prints. Plus, it is relatively much cheaper than blue tape. Between uhu and the generic brand gluestick, we would go for the generic brand again if we run out of it. Reason being it works better than UHU gluestick (generic brand being PVP-based) and plus-points for being cheaper (a quarter of the price per gram). So folks, we have experimented using 2 brands of gluesticks on cold glass print bed and they work well for PLA prints. Will you be trying it soon? (:   -yunfun


3D printer calibration prelude: Things to set before your first print/calibration

  Hey there! This is a checklist before you generate the gcode and hit that alluring "print" button in your host software(repetierhost, pronterface etc.) on your PC. I'm using Marlin Firmware on RAMPS 1.4 + arduino mega, strapped to an Ai3 printer. Step 1: Steps/mm of the printer axis and extruder Have you set the correct values in the firmware? If not, please follow this post (Calibration basic 1: steps/mm values). Step 2: Layer and perimeter Before generating your gcode in Slic3r, you have to set the intended layer height. 0.1mm for really detailed prints, to 0.3mm for rougher prints. For the first print, i would set 0.3mm Shell perimeter(or thickness) should be set sufficiently large for printing object that requires structural integrity. You can leave this as default for your first print. Step 3: Infill Infill is the region of print inside the hollow parts of an object, usually expressed as a percentage. Typically 60% or less for printing ornamental objects. 80-95% for printing objects with structural strength. Step 4: Speed How fast do you want the print to run? For the start, I would recommend 30-40mm/s. After tweaking and calibration, the Ai3 can go up to 140mm/s. Also, speed is inverse to print quality. If you want the print to turn out nice, you would not want to go too fast (: Step 5: Skirt, Brim, Raft, Support Skirt is basically a function that tells the printer to print thin loops around your actual print first, before printing the actual thing. This is rather important as it prepares the nozzle and its performance before printing the actual thing. The start of the skirt printing will consists of some irregular filament extrusion, but don't worry, the extrusion should be consistent flowing after 1 or 2 loops (the irregularity at the start is why we want to enable skirt). Brim should be enabled if you have trouble having the print to stick on the print platform. We will cover the methods to help keep the adhesion of the print to the print bed in the near future! For now, it should be disabled by default. Raft is functionally the same as brim; To keep the print adhered to the print platform. Except, instead of printing a additional base surface around the actual print in the case of Brim, the raft option prints a... "raft" ("boat") under the the actual print. For now, it should be disabled by default. Support is used for generating support material for parts of the print that are overhangs. Imagine printing the letter "T" upright; The top horizontal bar of the "T" are overhangs (it hangs in mid-air). You would want to enable Support then. We will cover support generation methods in the future! For now, it should be disabled by default. Step 6: Filament Are you printing ABS or PLA? If printing PLA, the recommended hotend temperature is 200-220 degrees C. If printing ABS, the recommended hotend temperature is 230-260 degrees C. Every spool of PLA/ABS filament may be different. Some works better at higher temperature, some lower. You have to observe how the print is done to know whether you should adjust the temperature. If it is too cold, the layers do not stick well to each other. If it is too hot, you will observe some stringing/whiskers and blobs around the printed parts. Remember to set the filament diameter too. (: Step 7: Cooling If you have a print cooling fan (not nozzle cooling fan), you can enable this option to cool the print as it prints. Cooling is more important when printing overhangs, bridges, and layers with very small surface area (<1 cubic cm). Step 8: Level your print bed relative to the nozzle! This is a very important step. Leveling the bed does not mean making it level with respect to gravity (with a spirit level). It means making sure the nozzle maintains a consistent distance from the bed no matter what the X Y coordinate is. Adjust the height of the 4 corners of the print bed, as well as the Z-axis threaded rod to bring the nozzle closer or away from the print bed. You should be able to slide a piece of paper between the nozzle and the print bed at all 4 corners with slight resistance. A poorly leveled bed will cause poor first layer adhesion to the print bed and cause premature print failure.   Alright that's all for the prelude! After this you may want to look at 3D printer calibration basic 2: Extrusion width/layer height value. Keep a look out for more calibration guides!


3D Printer calibration Basic 2: Extrusion width/layer height value

  Hey there! This is part 2 of the calibration guide! This 2nd part should be done after firming up your printer's steps/mm value for the extruder(described in prelude and part 1). Or else, it will be an "error carried forward" for this 2nd part of the calibration. Much of this calibration guide is based on Reprap's calibration guide wiki. I'm using Marlin Firmware on RAMPS 1.4 + arduino mega, strapped to an Ai3 printer. The extrusion width/layer height value is a ratio (typically 140-160%) which defines the width of the extruded plastic on the print. For example, with a layer height set at 0.3mm and width/layer height value set at 150%, the extruded plastic by the nozzle on the print will have a width of 0.45mm. This value is important to calibrate as it affects the resultant dimensions of your printed parts, as well as the print quality. I'm using Slic3r slicing program to generate gcode from stl files. The expert settings (in the advance tab) in this program includes different value inputs for the different types of extrusion width/layer height value, e.g., perimeter extrusion width/layer height, infill extrusion width/layer height. We will be focusing in 2 of the values here; Default extrusion width/layer height, and infill extrusion width/layer height. (Not all slicing programs has this setting, i.e. Cura. ) Step 1: Default extrusion width/layer height Where to set it: In slic3r program (expert mode), print settings, advanced tab What it affects: The accuracy of the size of your print. Print this: Perimeter_Width.stl The default extrusion width for your printer should be larger than the nozzle size. This will allow the extruded plastic to "fuse" sufficiently with previous printed plastic layer. So, if your nozzle size is 0.4mm, a good extrusion width will be 0.5mm. You can leave this setting by slic3r program default, as it will automatically determine a value based on the nozzle size you entered earlier in the basic settings. The perimeter_width.stl consists of two parts that fit into each other snugly. You may only want to adjust this value when you find that if the two parts is too tight (decrease width value) or too loose (increase width value). Alternatively, you can adjust the perimeter width extrusion/layer height value instead of default extrusion width/layer height. Step 2: Infill extrusion width/layer height Where to set it: In slic3r program (expert mode), print settings, advanced tab What it affects: The accuracy of the size of your print. Print this: 20mm-box.stl Try printing the 20mm-box.stl with 100% infill. You aim to get a flat top of the box. If the top is concave, try increasing the value. If it is a convex, try decreasing the value. I find that it is quite hard to calibrate this step, and i usually just keep it at its default value. Afterall, we usually infill at 80-90% to get a rather solid printed part. (:   Alright that's all for this part of the calibration! Keep a look out for the next part soon!


3D Printer calibration Basic 1: steps/mm values

  Hey there! When I first completed assembling the i3, I was lost on how to go about calibrating my printer, or knowing where and which part of the printer I should start calibrating. So I'm writing this post to hopefully help the beginners out there and point out in a step-by-step method on how to calibrate your printer! Before the start of the calibration, make sure you have the necessary software (host, slicer, arduino IDE) and that the printer axis are able to move through the controls via the host software(pronterface, repetierhost etc.) Much of this calibration guide is based on Reprap's calibration guide wiki. I'm using Marlin Firmware on RAMPS 1.4 + arduino mega, strapped to an Ai3 printer. The steps/mm value is simply the number of steps the stepper motor needs to rotate to achieve 1mm of travel on an axis (or 1mm of filament fed in, in the case of the extruder stepper motor). Too high of this value set in the firmware causes the more distance travel than intended (and vice versa). Before printing anything, please read through the prelude as well! Step 1: Steps/mm of the printer axis Where to set it: Firmware, Marlin. Search for "DEFAULT_AXIS_STEPS_PER_UNIT" in configuration.h What it affects: The accuracy of the size of your print. Print quality. Dependent on your printer components and settings, the steps/mm setting differs. I use Reprap calculator to find out the steps/mm for each axis. The calculations should be theoretically correct. So far, I have not encounter any visible problems using the theoretical values. So, for example, if you have got 200 for both x and y axis, 2560 for z axis, you would set (200,200,2560, xxxx) where xxxx is your extruder's step/mm remain unchanged. We will adjust the extruder's steps/mm in the next step. Pun unintended :) Step 2: Steps/mm of the extruder Where to set it: Firmware, Marlin. Search for "DEFAULT_AXIS_STEPS_PER_UNIT" in configuration.h What it affects: Print quality. Dependent on the type of extruder you have, the value would range from 50 to 700. Direct drive extruders have values of around 70steps/mm, while geared extruders around 500 to 700. For the Ai3 printer, since it is using a direct drive, the value is approximately 76.3 steps/mm. You can check if the value is accurate by sending the command (via the host ie. pronterface, repetier host etc) to the printer to extrude 5mm. If the filament fed in is less than 5mm, you would need to increase the steps/mm value. If more than 5mm, you would need to decrease it. A simple proportion formula can estimate the amount of steps/mm to adjust: New steps value = (Intended filament feed length)/(Actual filament feed length) * Old steps value You may need to do the whole process a few times to get an accurate value. Alternative method: First, find out the extrusion width/layer height (expressed in %, usually 140 - 170%) in your slicer settings. Then, print this thin-wall cube with 0 infill at 0.3mm layer height. Next, measure the thickness of the thin wall. Intended wall thickness with a 150% extrusion width/layer height setting at 0.3mm will be 0.45mm. If the thickness of the thin wall measured is not 0.45mm +/- 0.01mm, you will need to adjust the steps/mm value of your extruder. Too thin, you need to increase the steps/mm value; Too thick, decrease the value. Simple? (:   Alright that's all for this part of the calibration! You may want to look at part 2. Keep a look out for the more guides!


Set up a base camp

Howdy! We've just set up base camp in Experience Centre @ Home-fix HQ, 19 Tai Seng avenue! The experience centre @ Home-fix is essentially a makerspace, where makers and DIY-ers call heaven. Read more about the makerspace here! We are very grateful that Home-fix allowed JP3D to showcase the 3D printers and have a space to work on them! We hope to see more makers joining us in the coming months! If you are interested to see our 3D printers, feel free to drop by during working hours. But before you come down to Homefix HQ, pop us a message first to make sure we will be around for your visit. Email me (YF) at ngoyunfun@gmail.com or message us on our Facebook page! The address for Home-fix experience centre: Home-Fix Building 19 Tai Seng Avenue Level 2 Singapore 534054 Here are some photos at Home-fix experience centre: Home-fix HQ building Go up to the 2nd floor and look for these glass rooms! We are in one of them! Look for our 3D printers. You won't miss them! (:


Monday blues….

Monday blues! Something to be happy about on Monday, 24th Mar! Our 1.75 PLA DARK BLUE filament will be on sale for S$27.00 instead of the usual S$30.00! http://www.justprint3d.com/shop/1-75-mm-pla-dark-blue/ While stocks last! (:    


We have a Facebook page!

Just in case you are wondering if JustPrint3D is still operating...yes, we are still alive! We have a Facebook page here and you can browse our recent events and track our recent builds of 3D printers! Our most recent event is a building/sharing session on our 3D printers on 8th March 2014. We hope the participants had a great time sharing their experiences with their 3D printers and also had some hands-on session in building one during the session!


Coffee at Melvin new house

We had a visit to Melvin new place this afternoon, have not meet since Maker faire. (Actually that is only a month ago.) I brought along my bigger Cube printer with Ian help on transport, and here are the photos; After seeing Mel spool holder, I have no choice but to ask for his .stl file to make a set to use later. But you will need some flange ball bearing to hold the spool in place.           Looking at the Bigger Cube printer frame, somehow I feel that the machine is not complete but actually 85% of the mechanical parts are in there. The new controller board is on the way to us and to be tested next 2 weeks. The Heater and extruder are ready, waiting to be fitted onto the machine when the frame and x-axis carriage is done. Sorry to those whom I promise to get the machine up and ready few months back. Things has being too hectic for me getting the stuff in, printing parts for some guys out there, getting the extruder design right, tri-colour slicer .......   Back to now, just like you guys out there whom wanted to try everything with when you can get your hands on. I was able to test new modification on the heater block with some access to a small milling machine. That is  actually a problem! As you can see, I am overloaded with all the ideas in my mind and finally taking more time to do it instead.(I believe that I am not the only one.) Here is a proposal to all out there in SG (Singapore). If anyone interested on our work, please contact me and we will see if we can work out a win-win and interesting plan. After lunch, we moved on to other stuff like quad-copter, controller and the on-line shop. The tables is changed from machines to laptops. Everyone is still shy with camera as usual and that's why you see only a leg there.  We ransack through Mel packed toys to dig out his 9 channel RC controller (Turnigy 9x). I was talking to him few days back on his quad-copter, controller and have to see it and find out more from him today. On to justprint3d.com. Frankly speaking, i was thinking that the on-line shop is not ready, but already plan to inform all - here we are! With fun, times flies. We call it a day there but for me its a new start of blogging life. :)    


GCODE print time

I was trying to find out the time require for printing, but not available on Repetiter Host. A search on google and found something useful there; - http://gcode.ws


Stepper Driver Board Testing 1

After cutting the strip driver board, there you have it - 24 pieces. (if don't believe, you can count in the picture.) We will assemble and test next week when the ordered components arrive.


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