jacquard loom – Page 2

October 10, 2015 by Tien Chiu 4 Comments

Some thoughts on troubleshooting

I have now debugged all the heddles (cross fingers that they keep working!). I’ve gone from this:

photo of flawed weaving — lots of flaws!

to this:

160 flawless picks on the TC-2 jacquard loom — 160 flawless picks!

Along the way, I’ve figured out how to replace stuck valves, malfunctioning pistons, and bent heddles. And, more importantly, how to diagnose and fix each. Tronrud Engineering provided excellent documentation, which really helps!

There are a few things left to troubleshoot. The strain gauge on the top warp beam is delivering strange readings (the strain gauges are used to monitor and control the warp tension). The auto-controlled warp tension doesn’t seem to be working properly, and neither is the auto-advance. I have sent an email to the support team asking for help in troubleshooting those three items. (I suspect that they are all part of the same problem, and that once we figure out how to fix the strain gauge, the others will fall into place.)

One of the side effects of having to fix a couple dozen tricky heddles is that I now feel much more comfortable with the loom. One thing I have noticed, in myself and others, is a tendency to regard equipment, especially complicated equipment, as something magical that only a magically expert person can figure out. And Amazing Grace is pretty darn complicated. So it’s easy (and very tempting!) to throw up your hands and leave it to the experts.

However, a wizard is simply someone who understands how magic works! And once you understand it, it’s not that magical after all. In fact, once you understand the system, it seems pretty obvious (in retrospect) how everything works, what caused the problem, and how to fix it. As long as you have faith that things will make sense eventually, and apply critical thinking, eventually you’ll figure it out.

And, in fact, that’s basically what’s happened with Amazing Grace. I went from a magical system – press the pedal and the shed magically opens! – to an understanding of the real, physical system, which in turn has helped me diagnose and fix the problems. What happens in the physical system is that the computer electrically triggers some coils, which in turn open up valves for the heddles that will be lifted. The vacuum pump sucks air through the open valves, which raises pistons, and since the heddles are attached to the pistons, the heddles rise.

Once I understood that, I could think critically about what might happen to bollux up the system. If the coil isn’t working correctly, the heddle won’t move. If the valve isn’t opening and closing correctly, the heddle will get stuck consistently up or down (depending on which way the valve gets stuck). If the piston gets stuck, the heddle will either get stuck halfway or else consistently rise/stay down when it shouldn’t – depending on where the piston gets stuck. And if the metal heddle is bent, the heddle gets stuck as well.

So diagnosing problems with the magical shed really comes down to figuring out which of four parts is malfunctioning. And that can be fairly simply done. If the heddle looks bent, replace the heddle. If you feel resistance while manually moving the piston up and down, the piston is stuck and you need to replace the piston. Run the coil test in the software to test the coils. And if all else fails, it’s probably the valve.

And presto, the system is no longer magical. (Or perhaps I’ve become a wizard.)

Speaking of magical, our socks have begun mysteriously migrating around the house again. Of course, once you understand the mechanics of the system, it’s easy to understand how and why it happens. Fixing it, on the other hand, may be a bit more difficult. Here’s Fritz the Sock Thief, caught in flagrante delicto:

October 5, 2015 by Tien Chiu 2 Comments

Debugging

I’ve finished warping Amazing Grace – threaded, sleyed, tied on, header woven. Now I’m on to debugging – fixing both my own mistakes and any malfunctioning heddles. Here’s where I finished last night:

Because the full warp is very dense, I’m debugging using a double weave draft – two layers of 2/2 twill. It’s a striped draft, exchanging layers every inch or so. That lets me debug each layer separately.

I’ve only found one threading/sleying mistake so far. Considering how difficult it was to thread, that is astonishing accuracy. Very happy about that.

I’ve found quite a few sticky heddles, though – mostly, heddles that get stuck in the “up” position. I’ve been following Cathryn Amidei’s advice and gently tugging downward on those heddles to help them down. After being manually lowered several times, they’ve started behaving properly. The next step is to fix the heddles that get stuck in the “down” position – much more difficult since they aren’t as obvious. I think I may switch to a 1/3 twill design; that should make those stuck heddles easier to find and fix.

There are a few things I still need to debug. The two warps have vastly different tensions, which means I need to read through the manual and figure out how to set tension on the warp beams. And I’m not sure whether the auto-advance is turned on. And a few other minor tweaks – nothing complicated or difficult, just getting the feel of the loom.

All in all, though, debugging is going very well – so well, in fact, that I expect to finish today or tomorrow. Since I had allocated two weeks for debugging, this means I’d better get hopping on the next steps. The only problem is that I have no idea what they are! I had expected to have six weeks to contemplate the question during chocolate season, but it looks like I’ll need to get cracking sooner. I’m grateful that things are going better than expected, but it is challenging me to think about design. Especially if this hot weather continues, I’ll have a lot more time for weaving than I expected.

Speaking of hot weather, this week’s chocolate experiments were only somewhat successful. I readied six flavors of caramels and two ganache flavors. Like this:

The caramels came out wonderfully, with perfect texture for cutting and dipping. However, the weather was unexpectedly hot – around 80 F rather than 70 – which made chocolate work impossible. My friend Chris (who had come over to help) and I made some valiant efforts, but it was simply too hot to get the chocolate to temper correctly. So, no finished chocolates from this batch.

That said, I did get to sample all the centers. Of the six caramel flavors, I liked the rosemary-thyme-honey, coffee, coffee cardamom, and cinnamon honey the best. The rosemary-vanilla was a bust – the rosemary overpowered the vanilla – and I used way too much saffron in the saffron-rose-cardamom caramels. I may try that recipe again, but with about 1/4 the saffron. The jury’s still out on the two ganache flavors (balsamic vinegar/goat cheese/honey and plain goat cheese/honey). They taste good now, but I want to wait a few days to see how the flavor evolves.

Since I will likely use only one of the coffee flavors, that gives me three new flavors to put into the boxes. Usually I try for 6-10 new flavors (a box contains 32 flavors plus candied citrus peels), so I’m halfway there. Unfortunately, the hot weather is predicted to continue through next weekend, meaning I probably can’t test chocolates next weekend either. I’m not worried yet, but I hope the weather cools down soon!

So back to the loom! I think it’s time for me to spend a day or two studying shaded satins in double weave. I may also start dyeing some weft yarns.

September 23, 2015 by Tien Chiu 12 Comments

Focusing on process, not end result

I’ve spent the last few days learning how to thread Amazing Grace. It sounds simple – the thread goes through the heddle eye, right? What’s so complicated about that?

Plenty, actually. To begin with, the heddles are 36″ long and secured by long, flexible springs at the bottom; this makes them easy to tangle. Second, they’re fixed at bottom and top: you can’t move them around the way you would on a shaft loom. And third, they’re quite densely populated – 15 per inch in each module, and I’ve got them stacked four modules deep, so 60 heddles per inch. All of which can easily lead to tangles, missed heddles, and other antisocial loom behaviors.

Here’s what the setup looks like:

Heddles on Amazing Grace, my TC-2 jacquard loom

The heddle eyes are just barely visible (click to enlarge, then look closely) – they are tiny, maybe 3/16″ on a side. I’ve been threading with a 1.75 mm crochet hook (the 2.25 mm was way too large), though I’ve also tried using just my fingers.

Fortunately, there are some tricks you can use to make threading easier. You can use elastics (or bungee cords) to hold the unused heddles out of the way. The heddles are easy to pick out if you look at the bottom of the loom, where they are attached in nice neat rows and columns. And if you are selecting heddles from the bottom, the tangles straighten themselves out easily.

Of course, it takes time to figure all of these things out. So rather than focusing on getting the threading done, I’ve been focusing on improving my process. With every set of threads, I’ve asked myself, “Is there a better way to do this? Is there a way to make selecting the next heddle less confusing?” And then I experiment with a new technique for the next set of threads. This has slowed my threading down for now, but will greatly increase my speed later. And I’m in this for the long haul.

Most people don’t think consciously about the process by which they get things done. That’s a pity, because refining your methods can both improve your work and make it easier to create. I’m passionate about evangelizing this, which is, of course, why I wrote a book on the subject.

Anyway, I have now benchmarked my speed at 1.6 heddles/minute. Still very slow, but with some more improvements to the threading process, I hope to get faster soon.

September 20, 2015 by Tien Chiu 9 Comments

Beginnings

Shortly after returning home, I was struck down by a nasty cold, which floored me pretty much all week. But I’ve made progress nonetheless: I wound two 880-thread, 25-yard warps, and, with considerable help from my friend Pat, beamed both of them onto the loom. Here’s what it looked like partway through the first warp:

The weights are 1.25-pound weightlifting plates; they’re called “gem weights” and are used by weightlifters who want very fine control over the amounts they are lifting. The folks at the weightlifting supply store looked at my a bit oddly when I bought 30 of them at once – normally you only need two. But weavers aren’t normal, are we?

I had some tension problems with a few threads in the black warp, but the white one went on smoothly and perfectly. Here it is, fully beamed on. See how flat the warp is on the beam?

And here everything is, ready for threading.

black and white warps, ready for threading onto the TC-2

I suspect threading will be a bit of a challenge: it is easy to twist the heddles around each other, and the heddle eyes are very small, maybe 3/16″ tall. Which made the threading of the test warp incredibly slow. Since I have 1,760 heddles to thread, and am still fighting off this cold, I don’t expect to finish until the end of the month. And then the first few weeks of October will be spent debugging the warp, coaxing sticky heddles into smooth action, etc. I expect I’ll only be able to weave a sample or two before chocolate season starts. Patience, grasshopper!

Speaking of chocolate season, I’ve started thinking about flavors for this year’s test kitchen. I spend all year collecting ideas, and then test them out during late October. So far I have 18 ideas – but because I can realistically test only twelve, I need to winnow them down a bit. So: salted rosemary caramels dipped in dark chocolate? Apricot fruit jellies with rosewater ganache? Fig and fennel truffles? Homemade goat cheese and honey? Or maple pecan marshmallows dipped in dark chocolate? It’s already hard to decide, and I haven’t even started yet.

So stay tuned…beginnings are happening, slowly but surely, in the studio and in the kitchen.

And here are Tigress and Fritz, ready for new things to start. Perhaps there will be cat toys!

September 10, 2015 by Tien Chiu 3 Comments

Off to the Schiffer Books Author Picnic!

Schiffer Books is having its annual Author Picnic this weekend, and I’m flying out for the occasion. They’re offering a bunch of useful seminars tomorrow, and then Saturday is the picnic. So I’m in San Francisco International Airport right now, waiting for my plane to Philadelphia. From there I’ll drive to Atglen – where Schiffer is located. It’s a very rural area in the heart of Amish country – sounds like a neat place to visit. B., meanwhile, will be staying home to entertain the cats.

I confess that I am not particularly interested in the seminars, though they make a nice excuse to go. My main reason for going is to meet the Schiffer team that will be producing my book – editors, design and layout experts, and all the other folks who are needed to get a book from manuscript to published copy. It will be great to meet face to face with all the people I’ve been corresponding with for the last year.

I am, however, not neglecting Grace. I’ve brought the Arahweave manual and The Woven Pixel for study while I’m traveling, and hope to get a better understanding of jacquard design while I’m away. Once I get back, I’m going to put a 25-yard warp in black and cream-colored 10/2 cotton onto the loom. This will not be a project warp. I anticipate spending the next month and a half debugging the loom setup (some heddles are sticky and will need to be coaxed into full service) and developing an understanding of jacquard design, i.e. weaving samples.

After that, of course, it will be chocolate season, and I won’t have time for weaving during chocolate season. Rather than let Grace sit idle, though, I’ve invited a weaving buddy, Pat Stewart, to guest-weave on Grace while I’m preoccupied with chocolate. Pat is a weaving genius, so I expect she’ll be exploring some very interesting things while I’m away. She’ll likely be using the same warp.

Once chocolate season is over, I’ll put on a new warp and start weaving actual projects. My plan is to start simple and weave a rendition of the SkySat-1 launch, then a photo of Grace Hopper. Both are technically simple projects. After that, I want to weave my phoenix design – perhaps incorporating real gold threads and fiber optic cable into the design, or using retro-reflective yarns, which I’ve always wanted to experiment with.

And then? The sky’s the limit. I’m looking forward to finding out exactly what a jacquard loom can do.

I hear the boarding call for my flight now, so I’ll end here. More later!