Installing a new hot end in the Creality K1 (Max)

In my ongoing battle to become familiar with the K1 series, I thought I’d write up how to replace the hot end (since I had one really clog on me the other day) – that is why I wrote up the post on loading and unloading filament, that some people (on the Internet) thought was gross overkill.

There is a service tube video of hotend replacement, but more explanation is likely necessary for some, so this is my attempt. The installation process starts about one minute into the video.

First, it would be good to show what comes with a hotend kit. The hotend (obviously), as well as a bag of screws to attach it to the printer.

Hot end in the silicon sleeve (which needs to be carefully removed to install)

Breakdown of the hotend with the sleeve removed

Now the process to replace it.

1) Make sure the printer is turned off

2) Add appropriate thermal grease to the upper end of the throat tube and insert the throat tube into the mounting hole of the heat sink. Some people say this is not necessary, but it can’t do any harm.

3) Insert the connectors of the heating tube wire and thermistor into the corresponding terminal ports on the sub-board. We are doing this now since it may be too tight to get the connectors in after the hot end is installed. Make sure the little alignment marks on the plugs are pointed down to fit in the slots the sockets.

4) Turn the bump on the bottom of the brass heating tube towards the front of the machine, then secure the hotend by tightening the (long) hotend fixing screws and the upper screw of the throat tube. During the tightening process, ensure that the hotend is installed vertically, and that the mounting screws on both sides of the hotend bracket are equal in force. There should be a set of these screws included with your hot end kit.

5) If you need to replace the nozzle (you shouldn’t need to do this with a new hot end), use the open end wrench and the socket wrench provided when you purchased the printer. Place the open end wrench on the hot end brass mount (to use as the opposing wrench). Place the nozzle in the socket end and tighten it into place. Do not over tighten. If you use a torque wrench instead of the socket provided you are only looking for about 2.5 – 3 Nm (Newton Meter).

Note: You should finger-tighten the hotend cold, but final tightening should be done hot (240C), to ensure a tight fit.

6) Turn on the printer and set the temp to 240C. Expect some smoke.

7) Tighten the two hotend fixing screws and the hotend set screw at the back of the heat sink, to ensure the hot end is secure.

8) Load filament

9) Check to ensure that the filament extruded properly during the ‘extrude’ process (or if you just push it through while the hotend is on).

10) Turn the hot end temp off and turn on the fans to let the device cool. Once cool enough to touch turn the printer off.

11) Align the silicone sleeve with the nozzle and slide it over the hotend, ensuring that the silicone sleeve completely covers the hotend and the nozzle is surrounded by the sleeve. Be careful of the wires and the thermister sensor, since they can be easily detached.

12) Reassemble the extruder fan cover – Pick up the fan cover, insert the model cooling fan connector into the corresponding terminal port on the front of the nozzle sub-board. Slip the cover over the two knobs at the top of the assembly.

13) Fasten the fan cover and tighten the two screws on the left and right sides of the fan cover.

14) Reassemble the AI Lidar (unnecessary on the K1) – Insert the connectors for the AI Lidar connection cable into the corresponding mounting port on the nozzle sub-board, then insert the alignment posts at the top of the module into the alignment holes on the mounting bracket and secure them with the two screws.

15) Turn the printer back on.

16) Recalibrate the printer. You should do this whenever you mess with the extruder – in my opinion.

I am sure I left something off, so I’ll update it the next time I need to replace a hotend.

Creality K1 extruder loading and unloading checklist

This printer has some features that are supposed to help you load and unload filament. The load and unload capabilities work well – when executed in a very specific way. If you just wing it, there is a high likelihood that you will clog the extruder. I didn’t believe this until it happened to me twice in one week. Here is my checklist for unloading and loading filament:

Unloading filament (these steps may seem like overkill, but it seems to be necessary, since you can clog the printer during the filament unload process very easily):

1) Turn on the printer and wait for the user interface to quiesce (settle down).

2) Go to the filament load and unload screen

3) Click on Retract and wait for the retraction process to Finish. Make sure the temperature is appropriate for the filament being used. During the process, the printer will extruder a small amount of the filament to ensure the hot end is up to temp and then retract the filament out of the hot end/extruder.

4) Unlock the filament lock on top of the machine. The picture shows the lock in the locked position. If you don’t do this, there is a high likelihood that you will leave some unwanted filament in the machine.

5) Take the filament Bowden tube (the white tube in the picture) off the printer. To do this remove the blue clip, press down on the black ring and pull up on the tube. I really hate to do this, but it seems necessary, based on what you will see when you pull it out — not the orange blur, which is a filament artifact dangling on the end.

6) Check for any strange filament extrusion artifacts and remove them. If you do not do this, the little blob of filament can lodge in the tube, the extruder, or the filament sensor! This is the voice of experience speaking, since I have had all three clogs take place.

7) Roll the filament back on the reel and remove the filament spool. Clip the filament in place so it does not tangle.

Loading filament

1) Cut the end of the filament at an angle (at least 45 degrees) and ensure that it is not tangled. Place the spool on the printer, so that it will unroll in alignment with the insertion tube.

2) Insert the filament into the tube at the back of the machine. Ensure that the filament doesn’t come off the spool in the process.

3) Push the filament through the tube until you see it reach the end of the tube above the extruder.

4) Make sure the lock filament lock is in the unlocked position.

5) Push the filament into the extruder. We’re talking about ¾”, at least. If you face resistance, wiggle the filament back and forth. If you cannot get the filament in (you will feel some resistance until it gets past the knurled filament driver wheels), you may have filament residue clogging the Extruder, but that shouldn’t happen if you follow the unload process mentioned earlier. You may also have a bend in your filament. Gently try to straighten it – if you get too aggressive with this, the filament will weaken and be increasingly difficult to insert. If this happens, just spool out some more and snip it off past the weakened area.

6) Once the filament is fully in the extruder, lock the filament lock.

7) Push the tube back in place and use the blue clip to help keep the tube in place.

8) Go to the printer’s user interface and select Extrude.

This will load the filament the rest of the way into the hot end, leaving a small pile of extruded filament on the machine bed that can be removed and thrown away. If you changed colors of filament, the new color should be visible in the extruded filament.

If you hear clicking during the extrude setup, that means either your extruder or the hot end nozzle is clogged and the drive wheels cannot force the filament through. You can try and unload the filament and clear the clog, but you’ll need to use the various tools available to unclog the system or you may need to replace the nozzle, since there could be foreign matter stuck in the nozzle that the little wire cleaning tool cannot push through effectively. Generally, when I get to this stage I replace the nozzle, since it should be recalibrated… after disassembly anyway.

If you didn’t hear clicking and are still not seeing extruded filament, check to ensure that the filament lock is closed. It will not extrude anything if the lock is not closed, engaging the filament driver wheels.

As I mentioned, loading and unloading seems to be a very tedious multi-step process, but it is much better than having a clogged system that you’ll need to disassemble.

Z offset now part of the user interface of the Creality K1

I was out of the country for a while (and got COVID again) so have not been working with my 3D printer as much lately. I did want to provide an update on one of my on-going concerns about the Creality K1 that was addressed by a firmware update.

The latest update to the firmware has been released that can be automatically updated from the K1 (or K1 Max) user interface. It addresses the need for on-the-fly Z offset adjustment.

To access the capability, you need to scroll down the system settings until you see the option for Expert mode:

Once you click on it, you’ll see some new options to optimize:

• Z offset
• Flow
• Nozzle PID calibration

I’ve not had a chance to dig into them much, but Creality now allows on-the-fly adjustment of some additional printer values. This should allow you to adjust the printer’s behavior, rather than to try and make allowances in the slicer(s) that you use.

Dice and marble football game

Last year I made a baseball game for our woodshop sale. It sold in the first 10 minutes of the sale for $40, so I think it may have been underpriced. The baseball game made all the football fans jealous, so now I working on a football game that is similar in format.

I found numerous games online, but they all seemed to have their action one sided – the offense rolls…

The offense gets to select the play category (passing or running), but the defense rolls to determine the impact of the play. Almost every play not involving a penalty is rolled on by both players. The board currently looks like this:

What is needed to play besides the game board?

Two or more people, and a variety of marbles (7 in total), 4 dice and a set of 10 yard down markers:

1. Two marbles of one color for the home score
2. Two marbles of a different color for the visitor score
3. One to count the down
4. One to count the quarter
5. One to show field placement of the ball

Some sort of timing mechanism. The length of a quarter should be determined before the game begins. For example, if you decide on 10 minute quarters, the game will be done in close to 40 minutes, since there are no TV time outs…

The down marker ‘chains’ are used to keep track of the 10 yards needed to reach a first down (see more about this in the section of the document covering downs). I 3D printed that element of the game.

The ball placement on the field is shown using diagonal holes across the field.

The rules are fairly inclusive of various game elements like:

• Onside kick
• Pass interference
• Two point conversion
• Touchback

The rules were a bit more complicated than I would have liked, but football is actually more complicated than I would have though.

A game play example:

The rules go into much more detail about how this works but an example may be nice.

1) The visiting team kicks off and they roll a 17. Since they didn’t roll a 3 or an 18, take 30 and subtract 17. The ball ends up on the receiving team’s 13 yard line. It is 1^st and 10 on the 13.

2) The home team (now the offensive team) states that they are going to do a passing play. They roll a 4 and 5. This is a Flea Flicker (+1D). The defensive team rolls a 2 and a 1. The ball advanced 3 yards. It is 2^nd down and 7 yards to go on the 16 yard line.

3) The offensive team says they are going to do a running play and rolls a 6 and a 1. That is an Offside penalty (-5). The offense loses 5 yards, and it is still 2nd down. The ball is on the 11, so it is 2nd down and 12 yards to go. Note that to move the ball 5 yards, you just move it back to the hole to the left at the same level.

4) The offense decides to do a passing play. They roll a double 4. This is a Pass Complete (+3D). The defensive team rolls a 5, 3 and a 4 (12). This advances the ball to the 23 yard line, so it is 1^st and 10 on the 23.

5) The offense decides to do a passing play and rolls a 1 and a 5. This is an Interception turnover (+1D). The defense rolls one die, a 3. The ball advances in the direction the offense was heading 3 yards, and the ball turns over to the defense. They pick up the ball on the 26 yard line and it is 1st and 10. Not ethat the yard marker is pointed the other direction.

The Vistors (now the offense) are going to do a passing play and roll a 3 and a 6. This is a Pass complete (+1D). The defensive player rolls one die and rolls a 5. The ball advances to the 21 yard line and it is 2^nd down and 5 yards to go and it is second down.

Since they are halfway to a first down, they decide to do a running play and roll a 2 and a 3. They are Stopped (0). It is now 3^rd down with 5 yards to go, with the ball still on the 21 yard line.

They decide to do a passing play and roll a 3 and a 6, a Pass Complete (+1D). The defense rolls a 2. It is now 4^th down with 3 yards to go, the ball is on the 18.

The offense decides they are going to attempt a Field goal. The roll a 6, 2, 1 and a 6 – for 15. They rolled more than 6, so the kick is not blocked. You take the location on the field (18) and subtract the 6 to end up with 12. Subtract 25 from that and you end up with -13. Since that number is less than zero. The field goal was good. It is now Home: 0, Visitors: 3.

The visitors kick off again to the home team and they roll 12. Since they didn’t roll a 3 or an 18, take 30 and subtract 12. The ball ends up on the receiving team’s 18 yard line. It is 1^st and 10 on the 18.

The home team is on the offense, and they decide to do a running play. They roll a 6 and 4 – an Off tackle (+1D). The defense rolls a 4. The ball advances to the 22 yard line and it is 2^nd down and 6 to go.

The offensive team decides on a running play and rolls double sixes. It is a Touchdown!

The offensive team decides to attempt an extra point. They roll a 5 and a 6 for a total of 11. The defense rolls one die (3). 11 – 3 and end up with 8. Since the result is greater than 2, the extra point is successful.

Home: 7, Visitors: 3 

Creating manual tree supports in Orca

I was having trouble supporting the Catalina Blister. I was creating the supports by hand in my previous post.  One issue was not just supporting the large horizontal elements, but the near vertical elements were just too long, and vibration was making the part surface rough. Another issue was the posts on the outer cowl that the inner mechanism had to fit in and rotate around (see the hole at the bottom of the inner mechanism in the picture). If you have done any work with 3D printing (especially if you have printed a hinge), you’ll know that 3D prints are only strong in two dimensions.

I watched a YouTube video on the new organic capabilities of Orca. It explained the support creation capabilities in detail. One of the features that I investigated was ‘painting’ on the model where you want supports. After just a bit of work, I ended up with the following being generated.

Note how the long vertical elements should be prevented from vibrating much during the build by the supports. Since my printer is now finely tuned (see all the previous posts), I was able to remove the supports with little issue. The technique used was to take some diagonal pliers (snippers) and snip the supports off a branch or two down from where they touch the part, allowing me to apply leverage to only a small part of the model at a time, to snap off the support.

I am happy with the support that was generated after I told Orca where the difficult areas were. It didn’t take up too much plastic or time to create since they are hollow and only a fraction of a mm thick. One thing I did learn was to be careful with the ‘fill’ painting to support, since filling an area will make it difficult to remove the support if ‘the paint’ covers too much.

Using the live hinge

The G gage train that we have at our woodshop has sound automation that can be activated by pressing buttons. The kids who visit seem to like it. I always thought the 3D boxes to hold the electronics were always a bit klunky, held together with tape.

Now that I am using a UART controlled sound card, I thought I’d redesign the enclosure to have circuit, speaker, and connections in a self-locking box. There is one connector for the power and one for the switch interface.

The design now looks like:

The speaker will be on one side and the 3 small circuit boards (power converter, Pico and UART sound board) will be on the other. It should all close up nicely into a safe, relatively waterproof box.

I did the box design in Fusion and added the holes for the speaker and connectors with 3D builder. I could have done the whole thing in Fusion, but I find 3D builder quicker for rapid prototyping.

I am still using some buck coverters I had lying around, otherwise the design would be a bit narrower, though the speaker prevents it from getting too much smaller.

I’ll include a picture after the first one is done (if I can remember to update this post).

A parametric live hinge box model

I saw an article on creating live box hinges (hinges that bend to keep a box top and bottom attached when open). I took it as a challenge of my parametric design skills.

Live hinges have numerous advantages:

• Low-cost: Because of their simplicity, living hinges are cheap to make with 3D printing.

• Simplicity: Living hinges are integrated into parts, eliminating the need for extra components. The design can be easily altered.

They also have some issues:

• Durability: Since we are talking about extruded plastic here, multiple bending will cause fatigue and breakage over time.

• Appearance: They are not as subtle as a traditional hinge since the banded hinge sticks out of the design.

• Materials: The material you make the model out of needs to retain its flexibility over time. For example, PLA becomes brittle as it absorbs moisture from the air. I made mine out of PETG.

There are several approaches to the creation of live hinges:

• Hinged at the top with a relatively short hinge – requiring the design to be vertically oriented to print. This approach also has a relatively small area that takes all the stress.
• Hinged at the bottom with a longer hinge – this should allow for the design to be printed with maximum surface on the 3D printing plate. It also spreads stress over a wider area.

Since 3D printing is only strong in 2 dimensions, with the layered dimension significantly weaker, I decided to design for the longer, hinge at the bottom approach.

Fusion 360 supports parametric design, so I had to determine the critical dimensions that defined the design. These are what I ended up with:

The design itself is rather simple:

You can see from the design history (the timeline along the bottom) that there were not that many steps involved. When you change the boxLength, boxWidth or boxBaseHeight, the model updates to accommodate these new dimensions.

I learned a lot along the way since it took several iterations to get the model this simple. There are so many ways in Fusion 360 to accomplish a task that finding the optimal way can be a bit frustrating whenever you tackle a new approach.

Here are a couple of examples (note that they are different sizes):

The model is out in Thingiverse at:

Parametric live hinge box by cebess – Thingiverse

Prusa

I have continued to dig into the structures issue with 3D printing and REALLY wish these tools would export the structure as an STL file, rather than just G Code. I tell people there is no perfect hardware and there is no perfect software, so this just reinforces that perspective.

I did dust off Prusa slicer and set it up for my printer (I hope, since there are still a few questions about the setup process). It supports organic supports:

Now my big question is how well the structures will come apart…

I managed to print the bubble support

In the last post, I started to build the structures to support the complex blister struture. Here is a print in progress.

It managed to print OK, but the top structure was a bit thready (for lack of a better term), do to poor bridging. Note that the brim is almost touching between all the various elements. There is no way that it is going to pop off mid-print. I ended up creating the horizontal support structure every 10mm all the way up. It might be overkill but it is definitely cutting down on vibration.

This makes me want to research some of the more organic (or tree) scaffolding techniques that are described online. I have and use cura so I’ll give it a try and update what happens. My main goal is to have minimal support material consumed and maximum support for the horizontal plane located high above the plate.

It looks like it should be much faster but I am a little worried about those side supports going sooooo high without any kind of support. I may end up with a hybrid of hand made supports and the tree support.

Creating the supports to print this blister

As I delve into the issues of printing a structure as complex as the PBY blister, I need to build upon my existing knowledge of 3D printing sparce models. I learned long ago that when you are trying to print aerodynamic structures, it may be useful to split them in two and print the front separately from the back (especially if it has an irregular base). This allows the print to taper to the top of the print’s orientation.

I split the design at the widest point and then built a structure of columns that should break away.

Here is the support structure I have in the works now:

Note that I also printed a brim to keep the whole thing stable. The slicer generated support structures were a bit odd, and would take FOREVER to print, so I decided to hand build this one. The design approach was to create a set of columns in srategic weak areas. Once they were place, used a sketch to create several base plate/cross members that were 1mm thick between the columns that were the same height. I then used a repeating verticle pattern every 10-11 mm all the way up. The hope is to keep the support struture rigid enough to actually provide support, without consuming too much material. I don’t care how clean the spans/bridges are, since they are all getting thrown away. Here is a view (from a different angle) of the support struture in Fusion 360.

We’ll see how it prints, since this is a learning process. Looks like it will take 10 hours to complete, but I will probably know in about an hour (after it gets a couple of the stiffening structures done).