Kossel Pro 1.1


Both Tom, our machinist, and I have been sick for the past couple of weeks.  Both of us are on the mend, but it does throw a wrench into the schedule.  Anyway, for those who have received a tracking # for their Kossel, it should be on its way to you on Tuesday.  For those who still haven't, please send an email to: kickstarter at openbeamusa dot com.

There are a few things that have been going on, with regards to the Kossel Pro.

All metal hot end:

The weakest link on the original Kossel Pro was the OpenBeam J-Head clone.  While it resolved some of the things that I didn't like about the original J-Head, it was a dated design, and horribly expensive to produce (and would be more so, in the next year, as global PEEK production dwindles).  The thermistor wires were potted in and not user serviceable.  Even bigger issue was that the J-Head costs a whopping $100.00 to produce, and the market wouldn't really bear more than $60.00 for a completed J-Head (or really any print head for that matter).  We've shipped over $1000 (in replacement cost, to us) of J-Heads as warranty replacements to our backers and believe me, it hurts.   

With all these drawbacks, we've been fast tracking the engineering to create a replacement print head.  The following micro frogs were printed on one of the early all-metal prototype print heads:

The new print head, which I'm going to un-creatively name the K-Head, traces its design lineage to the E3D V6.  We took referenced the E3D's nozzle and heater block designand made a change to the heat break to remove any ambiguity on the assembly process by adding a flange to the heat break to positively register it against the heater block.  We also changed the configuration on the cooling fins to make the heat sink compatible with the Kossel Pro's end effector.  The results speak for themselves; the micro frogs you see above are straight off the printer, printed with a 0.4mm tip, sitting on a US penny (international readers:  19.5mm diameter).  We have tips down to 0.2mm that are coming in for prototyping and testing.  We've kept the thread size of the nozzle at M6, so nozzles will be compatible with E3D's nozzles.  

The new print head will be built from a combination of Chinese and American made parts.  We've had a heck of a time finding machine shops that would talk to us or make small enough quantity parts, or give us a proper lead time estimate, but we now believe we'd be able to get the first round of prototype heads in hand in about 2 weeks, and hopefully scale up to full production in 4-5 weeks.

As a thank you to our pre-built machine backers, we will be offering the all metal print head as a complementary upgrade (and we'll be using your machines to dial in the new print head print profiles, since this would be one of the few times where we'd be able go get a sizable fleet of Kossel Pros lined up).  All of the machines that MatterHackers will be selling, will also come with this new, all metal K-Head hot end.  (EDITED TO ADD:  We will also be offering the new all-metal hot-end at "cover our costs" pricing for our existing shopstarter and kickstarter supporters)

Pre gluing the Carbon Fiber Swing Arms.

One of the biggest challenges of building a delta printer is fabricating the ball joint swing arms.  We've engineered a no-compromise fully ball bearing swing arm set, and we've included the fixture parts in all our kits to allow people to glue it themselves, but gluing the arms accurately is still a pretty hard endeavor.  

Starting with the machines available from the MatterHacker's preorder page, we will be delivering the machine with arms pre-glued, on a calibrated gluing fixture.  This will eliminate a HUGE variable that stands in the way of getting awesome prints.

Prebuilt machines:

Nick, our new engineering tech, had been doing a wonderful job building these machines:

After the machines are built, we'll start the fine tuning process (and also a good time to validate print profiles across multiple machines).  We'll also  use this time to roll in some of the community-originated updates.  Finally, we'll need to engineering packaging that can hold the machine and survive UPS shipping (another set of drop tests, to test the new packaging for the box.  Plenty of stuff left to do, but we are pretty confident in our ability to deliver.

New Packaging:

From a logistics standpoint, packaging and kitting the Kossels (to get all the kickstarter and shopstarter machines shipped damn near killed me and Mike.  We did what we had to do to get things out the door, but it was not a sustainable process.  What is sustainable is moving the kitting and packaging process overseas to a competent contract manufacturer and paying someone overseas for kitting operations.

Here's a sneak preview of the new packaging:

One issue that we've keep coming back to, is that it's awfully hard to do small scale manufacturing here in the US.  I was at MD&M West a few weeks ago.  When I hid my day job's trade show credentials and went to talk to a few cardboard box makers, they didn't even want to give me their business cards when I mentioned that our top seller (the OpenBeam precut kit) is in the 500 to 1000 units per year range.  Across the ocean, however, Chinese box vendors would love to take our business and make us 500 custom size boxes, or print us 500 labels on a roll, or sell us 200 custom made heater cartridges.  The cost of a custom box cutting die cost less than what Mike and I spend for lunch every day.  When  you add in the fact that import tax laws tends to favor big companies (allowing finished goods to come in tax free, but throwing up huge paperwork barriers for small businesses bringing in individual components and trying to kit in the US) going with an off-shore contract manufacturer just makes things a lot easier.

Most of my time the past two weeks have been spent on overseas manufacturing documentation and kitting instructions.  Part of this is because of the longer lead times required to spin something overseas up as well.  Overseas manufacturing transfer will be the subject of another blog post down the line - we had to learn a few lessons the hard way, but I think we've got the process going pretty smoothly now, and hopefully we'd be able to smooth out the bumps with the next batch of printers coming in soon.

End User Documentation:

We've been slowly adding to the end user documentation, you can see the latest pictures taken for them here.

That's it for this long, overdue update.  

-=- Terence & Mike