Infill layer discovery.

I just remember I have a blog. Is a bit dusty but why not give it a try and give something back to the internet. This is mainly about 3D-printing.

So I have dipped my toes in a new hobby, Quadcopter flying. This mean some crashing which mean my 3D-printer will have to do some work. I made some alteration to some legs I found on thingivers.com and here it is in all is glory.


I few days later and this is what it looked like. I hit a tree and then the quad hit the ground. I thing the wind I my inexperience had some thing to do with it.

Anyway. A new arm take some time to get shipped and I do have the RepRapPro Mendel that should be able to do the job. I haven't been using my printer that much lately because of lack of time and relay no need and then there is this insane calibrations and testing that has to be done before a print succeed. It might be just me but I never felt I'v master it. During my attempt to print a new arm I found some thing I have not realised before and I thought I share it. It might be common knowledge but if so I have missed it out there.

The printing of the arm.

I downloaded a new arm from thingivers.com, http://www.thingiverse.com/thing:181301. With not much calibration I manage to print one. Honeycomb infill pattern and maybe 50% infill, I don't remember.

However it had some strange things going on. I imported the .stl in sketchup and cleaned it up and beefed up some parts I thought was a bit to thin. If it hod during flight I publishing it on thingivers.com.

With the honeycomb pattern for infill I figured I could get away with only 10% infill so I change to that.

I started a new build and after making sure it started ok I went to bed. This is what I found next day.

I haven't figured out exactly why it failed but I have an idea.

Printer upgrade to come.

During this time I also printed some new parts for the printer to upgrade the x-axis to the new design of the RepRapPro Mendel. They came out ok but do have some holes in the top and some other imperfection. I think they've will do so I have no plan redoing them.

At one time during this print one of the bearings on the x-axis on the printer come loose. I think it is related to the failure of the second attempt to print the quad arm but I didn't know that then.

Callibration

I thought I make an effort and calibrate the printer some more and specially the bride capability. http://www.thingiverse.com/thing:269679. I never rely made bridging work before and when trying now it was not pretty.

After some testing with the speed and the flow I had something I could live with. It is not perfect and wont win any contests but it will do for the kind of stuff I see me doing. What I ended up with as for settings is a low bridge speed of 20 mm/2 and a bridge flow ratio of 1.2.
Back to the arm.

Two more tests and 2 more failure.

The first one I didn't see, that's the upper one, but the bearing was off again. The second I say when it started doing the infill layer before the top and it was a disaster. What happen was that the layer did't lay down smoothly but curled up and made high spot over the howl area. Since the area is big they cool down and become hard. Then when the hotend was speeding back to the other side along the whole arm to do some printing it hit those spots and that was a bumpy ride. It made the print go of alignment and I guess this is also what made the bearing come loose. I stooped the second print asap.

Some thinking and searching I formed an idea about what was wrong. With low infill, in my case 10%, laying down the first infill layer is like birding but is not treated like that and I had not calibrated that. I use Slis3r and there are different speeds for the two. With that in mind I did some more tests.

Test test test.

Here the first one is with original settings and the second has infill layer settings close to my bridge speed settings. It's not much of a different but the second is a bit better. I figured it has to do with box being to small to show the effect of low infill.


 

I made a bigger one and stopped the print after it started the second layer.As can bee seen the first infill layer is much better then on the two failed quad arms.
A new arm.

Time to test my new found knowledge on the arm. Success!

I did change the infill to 15% so it probably helped some to.

I realised I don't need the small leg since I'going to make some smaller ones to put under the hub of the quad. Like the ones found here, http://www.thingiverse.com/thing:34562.

Some kind of conclusion:

There could be more tests done to rely nail this down but I leave it for now. This is what I think is going on.

When having a low infill the first infill layer starts looking like a bridge and the settings need to be calibrated much better.

With high infill the quality of the first infill layer seams not to matter as much probably because the next layer will compensate and hide problems to some extent.

I don't know what would have happened if the hotend had not taken the path over the high spots. It might have heated them and smooth them out on its next layer.

I guess that depening on how much the highspots cools down also plays a role in how well the second layer can hide it.

Looking at my first print one can wonder why it mad it through the whole print but I think it has to do with the high infill making the honeycomb pattern small which makes it much easer to get the layer flat.

I hope someone will get some help from this.

Woodturning Day 4

So, last day, a bit sad but my body started to complain about standing up for four days straight. It's just not used to it. Nothing new this day, everyone continued with what they wanted to do. I thought I'd make another "Tipover-Top". I didn't get it round so it didn't tip over as it should have. On the test run it went between the floor and Egil and ended up under the tugboat. After some looking around I found a trapdoor in the floor and could retrieve the "Tipover-Top". Well, now I have seen Egil from the underside, I don't think it's part of the regular tour in the museum.

We talked about buy a lathe but unfortunately the market for lathes in Sweden aren't that big. There aren't much to pick from unless you wan't to order from outside the country and the prices are high. There are a lot of used lathe for sale but it's a problem to know what it is and if it is a god one. At the moment I have two so I'm not actively looking for a new one, but you never know.

I decided to make a small cup. I first turned a ball with a handle, then I took a new piece of wood and made a wooden chuck the would fit the ball. After that it was just a matter of turning the inside of the cup. Now it was't that easy to fit the chuck tightly to the ball but with some water on the inside of the chuck it held the cup enough to be turned


The day went fast and towards the afternoon the snow started to fall and we helped pack the car and clean the place. It's hard to believe that a woodturning course for 12 people can fit one car with a trailer. There some thought to what goes were.


It's been four rely nice days. I have learnt a few thinks that has improved my turning. Mainly the way I hold the tool and move my body. I used to move the tool by moving my arms, but that makes it hard to get those log stable cuts. By locking the arms close to my body and move using my legs I got much better results.

There's a new course in April but I have not decided if I will go. I know my wife would like to go and that would be rely cool. There were some talk about a course in carving and I'd like to try that also. Will see.

Woodturning Day 3

My body aces, it's not use to stand in front of a lathe for hours. Shoulders with I have problem anyway reminds me that there there. To day it was bowl day. In green and dry wood. Mainly green with is rely nice to turn, like frozen butter some say. As usal Åke when through to steps and then it was time to try it. I have done 3 bowl before so I had some ides on what to expect.

The bowl blanks were already cut to a circle and a hole had been drilled to fit the chuck. So the blank in the chuck and the tail stock up against the blank to give it some more stability. I had hope to use my on tools here but examine the I realized I had grind them to a different shape than the tools at the course and worst, they were not sharp. I must have spent the time wrong because I could almost see my image in the bevel but it would not cut wood if not pushed hard. So the course tool is was.

When the edges was gone I removed the tail stock, made a tenon to fit the chuck and then finished the out side shape. When rely nice. I think I'm getting the hang of this. I had gotten of blank with a bit of the center of the tree left and that is nothing you wan't there when it begins to dry. It's a high probability of cracking leaving that there. Last time I tried to remove one, it split the whole bowl. This time how ever, I remembered to do it before finishing the inside, this gives the side support and which makes it lees likely to split. That done I just used I regular bowl gauge to remove the main part of the inside.

When coming to the bottom the geometry of the bowl combined with the tool makes it difficult to cut the bottom clean. For this a gauge hook is used. It is used from the out side and in towards the center. Nice tool, will buy my one at the end of the course. The turnig went ok and the inside turned out ok for a beginner.

When finished with the inside the bowl is removed from the chuck and a face plate with a foam rubber is put in the chuck. The tali stock is then used with a hollow pot and presses the bowl against the foam. It's then just a matter of removing the tenon on the under side and make the bottom the way you like.

I made one more bowl from green wood. The same steps but different shape. When starting the inside I made the side thinner then I expected. When shining light through the bowl the light was not red as I expected but white. I continued to make the side thin just for practice and did't expect the bowl to live through it, but it did.

So for the finale I did a bowl out of dry wood. Same methods but trying to keep the bowl a bit thicker than  when using green wood. For some reason the last pass of the inside made it all bumpy and I couldn't fix it. The bowl started to wobble a  little so I guess I removed to much material from the side and tensions were released in in the wood making it deformed.

Her is the gauge hook with a home made jigg to sharpen it on the Tormek. Guess I need to make one of them in the future.

When I got home I put the two green bowls in the micro and dried them. The first had already started to crack when I left the course. The black at the bottom of the first one...I manage to burn it in the micro.

According to Åke it took about 20 min to learn us the technics and the rest is just practise this of those during this course. I think it took more than 20 min but the tools are few and the technics are basically the same. Mastering them is of course a noter matter. Thats all for day 3. Tomorrow we will continue with what ever we feel like and I think I will do some more "Tipover-Tops". If you have't visits Åkes site take a look. I make a link that will translate it to English using google translate.

Woodturning Day 2

To day we continued to work between centers. Åke started by talking about how to sharpen the tools at the course. He uses a combination of a Tormek to get the shape back to original and a some Japanese water stones to hone the edge. This is a simple and easy way which is needed during a course like this. He has a system of colors on the different tools to match jigs and settings on the Tormek. To make the world understandable as he says. It makes it easy for the participants to sharpen the tools without risking to changing the angle of the bevel every time.

He then went on to show how to make a tool handle for a turning tool. It goes something like this. Make the the blank round, then drill the hole in the tool handle using the lathe and a long drill. Then using a tenoning tool make a tenon on the handle. Remove the handle and fit a brass ring on the tenon. Handle back in the lathe and make the shape  you prefer on your handle. Then tenoning tool is some thing I need to make.

Spinning Tops
After that it was back and continued with what we had left from yesterday. After I rought turned a blank it was time for another demonstration. The spinning tops. First a simple standard and then the "Tippe-Toppen". I have no English translation so I call it "Tipover-Top" for now and if anyone knows what it's called leave a comment. I've been wanting to make one sense last course but didn't know how.

 The standard spinning to went ok. Not that hard but it has it's moments so it's a good exercise with the smaller gauge. I realizes when comparing my gauge with the course tool that I had giving it a different shape. It was almost impossible to start the cut the way I was suppose to, but at least my gauge was sharp, rely rely sharp. I once again learnt how sharp the tools are and that the pointy part should never touch the inside of you hand. Don't ask me how I did it, it just happened. Not much of at wound but irritating to have it in my hand.

The Tipover-Top

The making of the Tippover-Top is fun. You have to make a round shape and excavate it some leaving the handle. Much can go wrong. But it didn't. I even took the skew and made the surface smooth. No catch this time. Some paint from a magic market and a test run and it worked! It's not guarantied that it works. The shape have to be correct for it to do it's magic. At this time I'm not sure why it does' what it does.

Åke then showed how to turn a mallet and then it was free turning until the end of the day.

My Tree

It's soon Christmas.
On of thte participants had a turned Christmas tree with him and that inspired me to make one of my on. While making the "Tipover-Top" I used the long point of the skew to remove some not needed material, that made some cool shavings and that gave me an idea for a Christmas tree. It can probably be improved a bit but came out rely nice I think.

To morrow we start making bowls in green wood.

Woodturning Day 1

So at last we are here. After a few years of to few interested the course is on. The course is held in the Egilhalen at Västerbottens museum. Egil is a tugboat now on display in the museum, you can see the stern of Egil in the picture. The course is 4 days and covers spindle work, bowl making and how to shape and sharpening the tools . The course is all about the cutting method with is the first method developed in woodturning. It was lost here in Sweden till about mid 80's when some guys want ed to learn the traditional way of turning and wrote a book about it. Maybe a separate post exploring the history of the cutting method in Sweden. The cool thing about the cutting method is the finished result. No sanding of the surface is needed. It is like the surface you get when planing. Smooth and shining.

Anyway we started of by Åke talking a bit about the lathe and safety and the then how to use one of the tools. The first exercise is just to turn a piece of green birch into shaving, with Åke had already turned rounds. Some of the people taking the course have never done any woodturning so it starts of rely simple. 500 rpm on the lathe and of you go.

The tool is a 19mm Robert Sorby finger gauge given a straight edge. This makes it simpler to use for beginner. Used correctly and carefulyl it gives a surface not far from that you get from a skew.

This is what you end up with, a of long shavings. I've used a smaller spindle gauge shaped more traditional on this one. You pretty much go you'r one pace on this course and Åke gives you guidens on the level your at which is relay nice.

Next exercise was to make an egg, which was done in dry birch. From square we use a 19mm gauge to make it round. Then with the smaller gauge two V cuts is made on both sides of what is to become the egg. I'm happy with the results. It's not perfect but is a tough exercise. Not everyone found there egg inside there blank;)

After this I went on making a practis piece with a v-cut, a bead, a cove and a up side down v-bead(don't know and can't find the english word for it). That conclude the day. Tomorrow we will continue do spindle work and I'll take more picture and continue reporting.

Last Notes:So that all for to day. Had a hell of a time trying to get this blog post together. Went a lot smother when I found a better editor than the standard on. Hopefully next post will go much better.

Time to turn

So, tomorrow it's time for a 4 day turning course. It is held by Västerbottens Hemslöjdsförening working with Åke Landstöm. It is a pure woodturning using cutting technics like in the old days. No scraping here. I have attended this course before but your never fully educated and it so much fun learning from a real master. I have now spent a few nights in front of my Tormek T7 and sharpening my tools so they'll be ready and I don't need to sharpen then that much during the course. There not perfect but probably sharp enough. I hope to take some picture during the course and write some about it.