Category: 3D Printing

Posted on

Tap shank adapter for 4mm AF hex drivers

Useful 3D printed adapters for hand tapping 3D threads

I usually 3D print all threaded holes as a modelled thread rather than tapping drill size hole which would need full post print tapping. As the intended thread size of modelled threads reduces so the print quality of the thread can be a problem. This usually leads to a quick post print run through the thread with a manual tap.

Thread quality and strength can be improved by increasing the number of perimeter prints via the slicer software. This makes the printer add extra print lines around all external surfaces before it does the infill. This is even more important if you are going to use brass inserts for your threaded mountings as it gives the insert more plastic to melt into.

The problem with post print clean up tapping is getting the tap to start perpendicular to the already printed tapped hole. If the hole is small (say M2) the size and mass of the tap holder adds to the wobble difficulty of getting it ‘plumb’.

In the past I would mount the tap in a small toolmakers chuck as this gave an extended length to the tap for the eye to judge the ‘plumbness’. I didn’t have enough chucks with the right size collet to cover all tap shanks.

Some time ago Clough42 recommended a small electric screwdriver that had 4mm AF inserts. I found this one on Amazon. There are also many other electrical and manual screwdrivers that use the 4mm AF insert standard.

It struck me that if I could make a set of adapters to mount in the screwdriver chuck to hold the tap shank this would ease the post print tapping problem. The length of this particular screwdriver body gave a better ‘to the eye’ perpendicular check. The added ability to electrically drive the tap meant that the perpendicular setting was more easily maintained. The speed and torque of the driver would also act as a break clutch.

I debated a lathe activity but then thought why not a 3D print? I created a model in Fusion with Parametric functions for the tap AF dimension and square driving section length.

Not all taps are created equal so these two parameters can be easily adjusted using the parametric function to match your tap sizes. Print time was around 9 minutes on my Qidi X Smart. I printed the adapters in PLA+ vertically off the bed as shown and in 0.2mm layer height. I set the slicer for 6 perimeters on the print, a 6mm wide outer brim for build stability and auto support off the build plate.

The adapter boss section will accomodate up to M5 size tap shank dimensions (3.9mm AF, 8mm length). Any size greater than M5 will usually print very clean and not need post print fettling.

Here is the Fusion file for those interested.

tapping adaptersDownload

Links to similar or related post are listed below : –

Posted on

Qidi Slicer auto support error on my part

Threads not quite to the design plan

The other day I modelled an adapter boss that had a threaded end to fit a standard CCTV camera mounting box (GB Pipe Thread – 26.441mm x 1.84mm tpi) and with the other end to suit a 20mm flexible conduit. Here is a Fusion pictorial view.

I modified the thread profile as per my post on thread tweaks and posted the file to Qidi Slicer. I opted to print in the orientation as shown above. This clearly needed support under the shoulder so without thinking I ticked the auto support tick box and hit print. The thread was a disaster flecks of filament such that it did not mate with the camera mounting box threaded hole.

Head scratching time, what had gone wrong ?

I had thoughtlessly just ticked autogenerate support and Qidi Slicer saw the thread profiles as potentially needing support and hence all the flash filament. Re-running with ‘support on build plate only’ removed the problem. See below.

This problem probably become more apparent due to the large size of the thread being modelled. Probably a dumb thing to have done but I tend to learn more from doing dumb things. One issue to be aware of in the future.

Links to similar or related post are listed below : –

Posted on

Qidi X Smart 3 revised fan installation

This is the final offering … well, for the time being ….

I have been slowly evolving my ideas for fume filtering when using the Qidi X-Smart 3 printer. I should say there is nothing majorly wrong with the fan system as shipped but there always seems to be background residual fumes even when printing PLA. The level of fumes does seem to be dependent on the brand of PLA used.

The rear fan as shipped has no HEPA filtering, it simply vents the chamber into the external air. This fan only comes on during the printing process.

I have previously posted some early ideas for improving this using readily available HEPA filters. Following some discussion with Christian, a fellow X Smart user, we worked together to evolve this further.

The first phase was to upgrade my external fan filter duct design to have both HEPA and a carbon granule filter sections. The carbon granules are sandwiched between two 10 gauge stainless steel meshes and an outer cover holds everything in place.

The result of this looked promising but the axial fan as shipped lacked a decent air flow through the filter stack. This was upgraded to a 6028 centrifugal fan mounted on an adapter plate. The Fusion 360 assembly is shown below.

Below is a simplified cross section view. The internal fan adapter plate flange and the external filter stack are bolted together through the back wall of the printer using the original fan mounting holes and M3 screws and nuts. The fan is mounted on the adapter plate using M4 screws and nuts. There are moulded nut cavities to make assembly easier. The cover plate which holds the two meshes and carbon granules in place uses M3 screws into 3D modelled threads in the corner holes.

As previously posted I had fitted a full size Bento filter to my Qidi ifast. Further discussion with Christian revealed he had fitted the Bento Mini to his X Smart and seemed impressed by the internal air scrubbing action. I looked at the design of the Mini and after some thought changed the carbon cavity filtering walls from a printed grid to using the same 10 gauge stainless steel mesh as used above. The Bento Mini printed well and I was impressed by the thought that had been put into the design. There is a version with a hanging bracket designed for the X Smart 3.

I now had a belt and braces solution – the Bento for internal scrubbing and the HEPA/Carbon filter pod on the rear extract fan. Here are some images of all the components in place and the small terminal strip to interconnect the 24V supply.

The fans used on both assemblies are the same dual bearing 6028 models as detailed in the Bento write up. These are rated at 24V @ 80mA. The axial fan originally fitted was rated at 130mA. I removed the original fan and wired the Bento and the extract fan in parallel and connected this to the original supply feed from the control board via a small terminal strip. The two fans are only commanded ON during printing.

That is my hopefully my last solution but as ever it will depend on actual performance to see whether I notice the difference in air quality. Mission creep is always possible.

As mentioned in a previous post, I designed some booster feet to fit over the existing feet on the printer. These increase the air gap below the printer to allow more air flow. If you print them in TPU they gave extra stability to the printer and reduce resonances.

Here is a link to the STL files and write ups for the simple duct, the fan adapter plate, the two stage filter duct, booster foot and also the modified Bento carbon box and lid with mesh divider walls. Note of late I have been printing with a setting of four perimeters which gives stronger modelled threads.

Thanks again to Christian in Germany who has been a great help in bringing these various mods to fruition.

X_Smart_compendiumDownload

Links to similar or related post are listed below : –

Posted on

Qidi X Smart 3 tweaks

Adding a LAN connection and other small modifications

From the title you will have guessed that I could not resist the temptation to buy an X Smart 3 while they were on special offer at GBP299.

The X Smart 3 is a lovely little machine. It prints excellent high quality models at a very fast speed. My testing suggests around a third of the time as on my Qidi ifast but of course it has nothing like the same chamber build volume.

I have had some issues with the X Smart 3, some of which were finger trouble on my part and some that needed recourse to Qidi’s excellent support team.

Attached to the link below is a ZIP file that has the full write up detailing my modifications to the X Smart 3 to add a LAN socket, modify the processor fan operation and to add extension feet to raise the body of the printer to allow more air flow. The ZIP file contains the PDF document and two STL files, one for the extension feet and one for a printed template to aid positioning the hole for the LAN socket.

Note that the LAN connection will not appear on the printer control panel but is visible by the Qidi Slicer application. The IP address allocated will be automatically defined and you will need an application like Fing to discover what this is. The control board will be discovered as a Raspberry board.

Qidi X Smart ModsDownload

Since the above write up I have progress on a HEPA filter housing for the X Smart 3 rear fan. Below is a write up on this and some changes I also made to my i-fast. Note that since posting this write up I moved the rear fan filter housing inside the chamber so that the fan is pulling air through the filter rather than trying to push it through. This worked out nicely with the rectangular shaped filter housing.

qidi_filter_filesDownload

I have also made a replacement top cover with a large HEPA so air can get in and out of the chamber to mitigate having to leave the lid off.

Update – Fan Noise

The only remaining frustration with the printer is the power supply fan noise. This is present all the time the printer is running whether under full print load or just on standby. Unlike the ifast the X Smart 3 only has one power supply. It is therefore impossible to get the power supply to switch off when it needs to be on to run things. Contrast the ifast where it goes completely quiet. There are suggestions that there maybe better substitute power supplies that have proportional speed fan control driven by the supply current demand. I debated this but decided there would still be noise even when backed off.

My solution is a bit steam age. I bought in an Alexa compatible AC switch. I now tell Alexa to turn the printer on and off. Much easier than trying to get round the back of the printer to the power switch.

On the subject of Alexa devices, I also bought in a Google/Alexa air quality monitor so I can check the VOC level around the printer. This seems to be quite sensitive and suggests the HEPA filter modifications are working.

Links to similar or related post are listed below : –

Posted on

Qidi X Smart 3 special weekend pricing

Worth considering ?

For those of you considering getting or upgrading a 3D printer, Qidi are offering their X Smart 3 on a special weekend price reduction from £399 to £299. This is a lot of printer for the price with a heated enclosure and fast printing speed. You can watch a review by Aurora Tech here.

I have no affiliation with Qidi but have a great respect for the company, their products and their superb support infrastructure.

Links to similar or related post are listed below : –

Proudly powered by WordPress
Verified by ExactMetrics