Glassblowing update

Now that the furnace is cold, I’ve had a good look at the lid. In addition to trimming the bricks back to 13.5 x 13.5 inches, I need to replace the metal strip holding the bricks in place.

The original plans from Mark required 4in galvanized sheet metal flashing, which I could not find. I took aluminum flashing and cut it into 4in strips, and that has worked fairly well for years. I’ve replaced parts of it at least once when the tightening mechanism tore the thin aluminum, but it seems to need replacement again as it’s been deformed by the too-large lid.

This time I plan to obtain some 4in sheet metal, somewhere between 24ga and 30ga, with me leaning towards 24-26 ga at the moment. As I cannot source a roll of 4in sheet metal flashing anywhere, I will try Metal Supermarket and see if they will cut me a few 4in slices off some sheet metal.

Stay tuned…

Glassblowing – last day (for now)

Today I made four larger pumpkins, which filled the annealer and pretty much emptied the pot. Afterward, I turned off the furnace, which will now cool from 2100F to around 50F over the next week or so. The furnace is very well insulated, so it takes a long time to cool.

Once shut off, I need to attend the lid that cracked and trim it to fit the steel frame more securely. I plan to modify the current lid (assuming the crack is not too bad) as well as the spare lid I made last year as both were made to the same size, which is definitily too long. Afterward, I plan to restart the furnace in the last half of November, unless the weather is really horrid.

Glassblowing update

Yesterday I blew glass again, making some larger pumpkins as well as some new color Christmas balls. I recently received my glass order from Sylvie at Colourfusion (in Ontario), and it included cobalt blue (opaque) and a light blue (opaque). The light blue with a cobalt stripe is really nice, as is the straight cobalt c-ball.

I also ordered and received a new 4in optic mold from Steinert Industries. This one is a beautiful ribbed mold that is closed on the bottom. My other molds are open bottom. The nice thing about a closed bottom is that it can be used for small or medium gathers equally well. This enabled me to make both small and medium pumpkins.

On Saturday’s session, the gathering port lid fell out of the steel frame as I was starting my second c-ball. It landed with a thump on the furnace. Although it cracked in half, it still covered the crucible. Thinking quickly (things are at 2000F) I was able to push the pieces together with my large tweezers and move the lid to where the steel support would fit and close. I was then able to adjust the attachment clamps to firmly hold the lid so I could finish the session. There was a bit of brick dust on the top of the molten glass, but I gathered it out easily on the next piece.

When I shut off the furnace later this week for maintenance, I will have to modify the lit to better fit the support.

As to the glass, the new bags of Spruce Pine are melting well. When I first received the order over a year ago August, the bags were rock hard and the batch had many hard lumps that would not break. For some reason, just sitting around in my shed for a year has resulted in batch that is still hard, but breaks up into nice batch with a single bag-drop onto concrete as is considered normal. The glass is also really for the entire pot. I do love melting Spruce Pine.

I’ll take some photos of the pumpkins and c-balls  later in the week and post them here.

Printer update

I’ve been busy blowing glass the past week or so, so haven’t spent much time with the 3d printers. I did print 8 more weight collars for the weight bench, installing 4 of them last week. They work really well and are easy to print. Printing 4 at a time is easy and takes about 2 hours. What  is even nicer is the new brand of filament is not jamming at all feeding the original cartesian printer, so I don’t have to monitor the print all the time.

The delta almost printed a nice cube. Only the base was off, and on reflection I think it’s because the setting for ‘probe offset’ is too large. The probe offset is basically the distance between the extruder tip touching the printer base and moving enough (into the base) to trigger the probe microswitch. There were two values in the Marlin firmware – 0.2 and 0.7. I’m using 0.7 right now and I think it’s too much, so when you calibrate the printer the final distances are out by a small amount. Not much, but just enough that the extruder is farther away from the bed on layer one than necessary for a proper first layer.

I need to spend some time with raw gcode to find the actual probe distance for my printer and then use that to recalibrate. Perhaps later this week or sometime next week.

 

FLSUN Delta not quite there yet…

I’ve been working with the FLSUN delta printer I built from a kit this week, and although it has printed a few of the test cubes, it’s still not quite fully functional yet.

It turns out delta printers are a lot faster than cartesian (x,y,z) printers, but with that speed comes some rather unique challenges. The first is that the printer, being tripod and pendulum based, really wants to print in an arc. To counter this, the software needs to know a lot of details about the printer, such as segment lengths and arcs in order to calculate various angles and offsets to use when printing.

Fortunately the delta code firmware I’m using (Marlin 1.1) now has an auto calibrate feature that works with the built-in z-probe on the FLSUN delta. Not all deltas have the z-probe, but it’s easy enough to add to any printer. Basically it’s a microswitch down near the extruder that detects when the extruder is near the print bed. On the FLSUN, the switch is triggered by a rather ingenious lever mechanism built into the extruder mount. When the tip touches the bed, it rocks slightly and trips the microswitch. You can fine tune the triggering pressure so that it’s very accurate. There is one compensating measurement you must take, and that’s how much deflection occurs when triggering. That is, the extruder doesn’t just touch the bed, it touches it a bit MORE than when printing to tip and trigger the switch. You need to know (in mm) how much this extra movement is so the software can compensate when calculating actual bed height.

The auto calibrate touches the bed in a set number of places that can be programmed (n*n, with n=4 as default). It can then calculate various angles and offsets that you then either save in the printer firmware eeprom or hand code into the software. I chose to hand code. The default calibration runs until a set standard deviation is achieved, so it’s quite accurate.

Once the auto calibrate is done and the information encoded in the firmware and uploaded to the printer, you can print.

My first prints were terrible. I quickly realized the extruder calibration was off. Extruder calibration is done with auto calibrate but must be done separately. Mine was barely moving, so after some experiments and adjustments, I got the correct parameter (stepper steps per mm of filament) and that was OK.

However, the next several prints were all still bad. I quickly found one of the three end stops that controls the position of the extruder was loose. After adjusting and tightening, things were much better, but there’s still a problem with the print.

The first few layers (about 1mm or so) are offset from the rest of the print in one direction. It’s consistent and repeatable at this time. The rest of the cube is perfectly straight, so it’s a “first layer” problem. So far I have not found any solution on the internet.

One hint that I’ll be pursuing is that the height measurement of the cube is only 19mm, while the sides are both 20mm perfectly. That implies again a “first layer” problem, possibly too hot. I am also considering the fact that this printer is incredibly fast. It’s almost twice the print speed of my first (cartesian) printer. It’s possible that it is simply printing the first few layers too fast, which may also affect the temperature of those first layers.

My next steps are to compare speed parameters between Marlin 1.1 (my current firmware version) and Marlin 1.0 (supplied with the printer) and my cartesian printer (also Marlin 1.1, but much slower settings). I will also try slowing the first layer in slic3r as a quick test. If slowing the initial print speed works, then that will be great. For now it’s a wonderful printer that has yet to realize all it’s benefits (and yet to make it’s first perfect print). 

“I guess I’m not their demographic”… Apple

I just had the most monstrous fight with apple software this week, and had to give up. All I wanted to do was prune my songs on my iphone and ipad. There were songs I wanted to remove that I had installed via itunes on my macbook some years ago.

Well, I couldn’t. Not easily. I finally used the general settings… remove all music feature to clean it up. The only other way was to delete each song individually by swiping left and then touching ‘delete’. Not whole albums, but song by song. How stupid and user-unfreindly!

The worst mistake I made was installing itunes on my Win7 pc. Dumb, dumb, dumb! It worked, but even after connecting the ipad and iphone, it would not let me actually TOUCH the songs. It was so brain-dead that after showing me “songs on the device” it would not delete – the only option was “copy to device”. BUT IT’S ON THE DEVICE AND YOU KNOW IT!!!

Today I blew away itunes. Of course apple left behind a puddle of other crap on the PC that I could not remove via programs. Fortunately I anticipate such nonsense, so before the install I had created a “before itunes” restore point. Using this I was able to recover my PC to where I wanted, not where apple wanted to leave it.

So now I have no songs on my i-devices, but I don’t care. The whole purpose was to use one as an alarm clock playing a random song each morning. Turns out it CANNOT be done via apple. The only way is to jailbreak the device.

As for apple, they don’t want me. They blew off objective-C for their own pathetic thingy called swift for i-device programming. That’s when I stopped app development. Then the recent crop of laptops (no desktops anymore) showed apple’s utter contempt for customers. “You can have light, or powerful, or good screen, but not all in one device. To get them all, buy more devices,” OK, I choose none.

Now the latest iphone is announced at a ludicrous price point. Honestly, the apple price and features list looks like it came from “SpaceBalls, the merchandising”.

Guess I’m not apples demographic anymore. Too bad. I really got the feeling that Steve Jobs understood me, what with us being the same age and loving tech and all. The new apple since Jobs just seems to be about “merchandising to the max”. Sad, really.

Letting the cat out of the bag (3d Printer)

OK, so I’m letting the cat out of the bag. Back in August I decided that I really wanted to try the new delta printers. They come primarily as kits, though you can buy one already  built if you are made of money. I’m not; besides I like building kits.

After much research including print and video reviews as well as many build videos, I chose the FLSUN Kossel Delta printer. There were several delta printers of almost identical value, but I chose this printer for the primary reason that it is “fulfilled by Amazon”, meaning that it comes from a N. American warehouse, not from China. That in turn means that it will arrive quickly. The price was also an incredible deal compared to many others.

It arrived in quick order, and everything was there. It was very well packed, and relatively easy to assemble. I did not make an “assembling of” video because those are pretty similar and all pretty boring, even at high speed. For the most part I followed the instructions to the letter, though I did deviate a few times when I could clearly see a better path. I only had to undo/redo one step, and that only because I wasn’t paying attention to the orientation of the extruder during assembly.

Some of the final steps were less than optimum, in my opinion. Mostly these involved routing and bundling of wires, and location of the main board and power supply. In the end I designed and printed some brackets to hold the power supply securely in a very nice location. I printed these on my other printer. I also designed and printed a spool holder to sit on top. There were available designs on Thingverse, but I really didn’t like them. I do like mine.

I will post photos of the spool holder and the power supply brackets later this week, as well as photos of the printer.

Once together, I did all the set-up, prep and calibration steps.

I still didn’t like the way I’d wired the power supply. I also didn’t like the fact that the power supply did not have an on/off switch, so I bought a switch/cord/fuse receptacle from Amazon (very inexpensive) and then printed a housing for it that sits off the end of t he power supply. It looks great and secures the cord (and all connections) inside the housing. Plus, now there’s an on/off switch for the printer.

I’ll post photos of the switch and housing later this week.

I have yet to make my first print with the printer, but it should happen quite soon.

Photos of recent 3D prints

As promised in my last post, here are some photos of the weight plate collar and the new regulator flow knob. Also a photo of the old knob for comparison.

Dacor Fury small knob

Dacor Fury new larger knob

Weight plate collar (the yellow spot marks an original collar)

This is a set of base brackets I printed to hold my PiDP8 kit at a better viewing angle (design from Thingverse)

Glass shop going hot again

It’s time to make some fall glass. Today at noon I started up the glass furnace. It’s a slow process: it takes 8 hours to heat from 100F to 900F at 100F/hour, then 16 hours to get to 1300F at 25F/hour, and then a further 6 hours to reach holding temp of 1900F.

Once it’s at 1900F, I’ll start charging with raw glass batch. The batch I use is Spruce Pine, or SP87 which is the classic batch for glassblowers. I should have a fresh pot of clear glass early next week. Then it’s time to make some nice things.