Mendel 90 full kit unboxing

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I ordered a Mendel90 kit from Nophead last week and finally got around to unboxing it.
Disclosure: I've known Nophead for 20 years and he agreed to let me have an early kit. The kit he supplied me had some parts in it that needed reaming, which I agreed to accept. Kits ordered here will be superior.
The kit has absolutely everything down to the last tie-wrap. Here are the printed and CNC machined Dibond parts:

There is so much in the kit I had to take two pics. Bear in mind that I already had the stepper motors and PSU/Mains lead which Chris agreed to leave out for me. Here are the rest of the parts:

Multitubinous

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I've been ask to design several custom IR focusing tubes for lasertag systems.

The first was for a short focal length, wide beam unit for use against vehicles. Laser-like focus is not good in this scenario as it would require a large target like a vehicle being covered in sensors.

I obtained 3 lenses in the 40-60mm focal length range and did some tests at visible wavelengths. This suggested that all 3 would suffice, but the customer agreed to take all three and decide for himself which was best.
I had to supply two focussing tubes as one of the lenses was 1.6mm greater diameter than the type I normally use:

I was also asked to design a picatinny rail mount for an IR focussing tube. This involved the design of some clamps to centre the tube on the rail. Here it is fitted somewhat impractically to the sight rail of an Airsoft gun:

And here in a more realistic position:

New Toy

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My old 'scope has finally been superseded. Bought this Tektronik 100MHz DSO from EBay whilst I was in Tallinn, Estonia last week.

I'm not a great fan of PC scopes as the software always seems a bit crap. So I went old school and bought this:

Lasertag bodies

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I've been manufacturing many lasertag bodies for Steve at Operation Lasertag. These differ from my standard kits in that they are designed to fit Steve's analogue lasertag boards, and they have coloured plastic parts to allow for easy team identification, as well as raised gun sights:

Luck + Failure

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I started a print for an order that Steve at Operation Lasertag has put in for some gun kits. I started a print off as usual, went into the kitchen to get a brew whilst listening to 'Today' on Radio 4. Radio 4 went off. Briefly I remembered something about Radio 4 being used to test whether London had been nuked. Coming to my senses I put 2 and 2 together and went to check the 3D printer. My 3D printer has a mains powered heated bed. I found this:

During the Z calibration the hot end had touched one of the bulldog clips used to fasten the print surface in place. Something had obviously shorted out the mains supply.
On dismantling the heated bed, I found that one of the 15W resistors used as a heater had gone OC, but had shorted internally to the case, raising the heated bed to 240V ac!!

I replaced the failed resistor and thankfully the hot end controller electronics that I use had survived intact, although the mains 5A fuse had blow. Lucky!
The first print I tried after repairs failed, but the extruder was playing up this time:

The fill had gaps. After checking the usual suspects, I focussed on the hot end. There had obviously been a leak as the grub screw used to fasten the nozzle in place had signs of something escaping:

Removing the brass hot end showed that the sealant I used on the threads between the brass and the peek had de-natured:

I managed to 'refurbish' the hot end. Cleaning the nozzle and re-installing with fresh sealant. There did not appear to be any internal damage to the peek/PTFE barrier. I'm waiting for the high temp sealant to set and will try again tomorrow.

Halloween Again

As I print 14 gun kits for a customer I find myself with some spare time...and it's Halloween soon.

I've been using my pneumatically operated skeleton/coffin combo for a few years now:



This year I got a cheap posable skeleton and I've a few ideas to try out. Test number 1: Skeleton swinging on gallows in (motor assisted) breeze. The motor is from one of the 10p hoppers we use for payout at work. It has a high reduction ration and loads of torque.

Tri-Sensor

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I've just completed a special build of my Milestag sensor domes for a customer. This unit incorporates 3 sensor domes for cap mounting with the rear facing unit housing the distribution PCB and coiled cable connector:

As usual, mountings are RepRap and the acrylic domes home baked.