Ikea Frakta (Blue) Bag Handle

 I live about a 100m walk from the garage where my car is parked to my door. I don't like to shop frequently, so I tend to load up, and that means getting multiple bags of groceries from my car to my condo. Someday I'll get some sort of collapsible cart to roll the stuff to my door. Until then I use a different means to schlep the groceries from the car to my door.

I keep two, blue, Ikea Frakta shopping bags ($1 at any Ikea store) in my car to carry multiple bags of groceries, or a bunch stuff to take to and from the makerspace, all at once. The only problem is that if the load is heavy, the bag's sewn-on cloth handle crushes my hand. Ouch!

I could have simply cut a slot in a piece of PVC pipe to make a handle, but PVC is hard and slippery, so it might be uncomfortable with a heavy load in the bag. To a hammer, everything looks like a nail, and to a man with a 3D printer, everything looks like a 3D printing project. I immediately thought to use TPU filament so it would feel softer in the hand than PVC pipe, and the ridges from the printing process would make it easy to grip. 

It took about 10 minutes to design the handle and prep it for printing- it looks like a piece of pipe with a slot cut in it! I used generic TPU, a 1 mm nozzle, printing in 0.5 mm layers with 1.2 mm line width at 30 mm/sec with 15% triangular infill, 2 perimeters, and 2 mm top and bottom thickness. It takes about an hour to print and uses 66g of filament.

CAD rendering of the handle. Pretty simple- draw the C shape, extrude, fillet the vertical edges, chamfer the top and bottom perimeters.

This is the handle printed in red TPU. It's rigid, but has just enough give to keep it comfortable. It's 120 mm long and 35 mm in diameter, which might be a little big if you have very small hands.

The handle in place on the bag. It takes a little effort to attach it to the cloth handles, and a little effort to detach it, too, which is good. 

An alternative location to store the handle- use it to hold the bag so it doesn't unfold when you don't want it to.

This handle should work with any other bag with a cloth handle and even dog leashes.

You can download the STEP file here.

Coasters, anyone?

I Needed Some Coasters, So...

The coasters are orange, the bottom of the box is yellow, and the top is pink, all at least a little fluorescent. 

I printed some coasters and a storage box for them using TPU filament. I think they came out alright.

These coasters are all 100 mm in diameter and 2.88 mm high (I printed in 0.24 mm layers) and the box holds a stack of six of them.  Each coaster has a different pattern. The patterns and the lip around the edge of each coaster are designed to trap condensation that dribbles off your cold glass so it doesn't end up on your furniture. I kept the patterns shallow in Z. If the patterns get too deep it starts to become a problem keeping them clean.

The box's lid fits loosely so it's easy to remove. You can put it under the bottom of the box if you turn it upside down. The rounded corners have enough space to use a finger to lift the coasters out of the box, one at a time.

Being printed in TPU, the coasters are great for hot and cold drinks, but I would not set a pot right off the stove on them. I tried washing them on the top rack in a dishwasher and they came out looking like they just came off the printer- perfect, but who knows? Maybe they'll show some wear after multiple cycles.

Printing

I used TPU because I like the way it looks, especially when it fluoresces. The photo shows the result of four printing sessions split among three colors. The first two sessions were to print three coasters at a time, one more session to print the box bottom, and finally one to print the box lid. 

Another reason to use TPU was because I liked the idea of the surface being a little soft.  Setting a glass or cup down on a soft surface will sound and feel different from setting it down on a hard surface. I have a granite counter top, and setting a glass or cup down on it always makes me feel like I'm going damage either the glass/cup or the counter top.

I printed at 240C- a bit higher than the recommended temperature range for TPU, but the plastic really flows at that temperature, yields a super shiny finish, and the interlayer adhesion is amazing. I get almost no hairs on the prints. They seem to be leakproof. Of course, with use they will probably start to look bad because spills will inevitably find tiny gaps between lines in the print that can't be properly cleaned out. It's no big deal - I have a 3D printer, so I'll just replace them with another set before they start to look bad.

Print speed was 40 mm/sec, no cooling fan, 45C PEI bed.

It should be easy to print these in as many colors as there are pieces (8 in total). You can do all sorts of crazy stuff, if your printer can produce multicolor prints.

You don't have to print with TPU if you don't want to. PC, ABS, PETG, or PLA, will work too, but you might have to be careful about putting hot drinks on PLA.

The box lid is printed with the top side down on the bed. My printer's PEI bed has scratches that transfer to the print, so the top cover doesn't look as perfect as the sides and everything else. I think printing on glass would be a good idea, at least for the top cover. 

It's easy to change the shape and size of the prints by scaling them when you slice the files to print. If you think they aren't deep enough just scale them in Z for the (any) depth you want. If you want larger or smaller or oval coasters (??), just scale the X and Y axes appropriately after you put them on the plater in the slicer.

I printed with concentric infill for the top and bottom layers and they came out with some interesting patterns.

Finally, clean the nozzle thoroughly just before the print starts, while it's at print temperature.  That will help prevent getting little blobs of charred plastic embedded in the print. Avoiding over extrusion helps, too.

STL files are here.

Floor Jack Pads: Pushing The Limits of 3D Printed Parts

My 12 year old Audi TT needs new shocks and I am preparing to do the work myself.  I've changed struts on two other cars, so I have most of the tools and a pretty good idea of what to expect.  Now I'm in the process of researching all the correct part numbers to order.

One tool that's been missing from my ever-growing collection is a floor jack.  I fixed that deficiency yesterday with a trip to Harbor Freight Tools where I bought a 3 ton, low profile, steel jack for $89.  I have no illusions about the quality, but it seems sturdily built (it weighs about 80 lbs) and should be fine for my infrequent uses like replacing the struts in my car and rotating the tires once in a while.

The jack did not come with any sort of pad on the saddle, and I don't want to try using it without one, so I did a little research.  Volkswagen Audi Group vehicles use a common lifting point "socket" that is best used with a jack pad that is made to fit.  I looked up commercial offerings and found some for about $8-10, made of polyurethane.  Polyurethane?  I can print that!

One of the jack pad makers was kind enough to provide dimensions:

Audi jack pad dimensions.

I modeled one of the pads in Fusion360 in about 30 seconds.  The commercial pad was only 69 mm in diameter but the saddle on my jack is 93 mm in diameter, so my model has a 90 mm diameter base.

My print used fluorescent green TPU- I won't have any trouble seeing it in the bottom of a drawer or toolbox.

UMMD has a 0.4 mm nozzle, so I used TPU filament in 0.24 mm layers, 0.5 mm line width, 6 perimeters, 8 top and bottom solid layers, and 40% triangular infill.  It used about 101g of filament and took about 5 hours to print at 40 mm/sec.  The print came out beautiful, and like all TPU prints, it's super tough.

Here's the jack with the naked saddle.  You need some sort of pad to protect the car!

Here's the jack with my custom 3D printed pad in the saddle.  The bump on top of the pad fits into the jacking receptacle on the car's frame.

Let's see if it's tough enough:


Well there you go!  TPU is one of the most amazing filaments you can get for a 3D printer!  It's easy to print (220C extruder, 45C bed, 30-40 mm/sec) and produces incredibly tough prints.

A view of the 40% triangular infill looking through the bottom of the Audi floor jack pad.

I used concentric infill for the bottom and top layers.  Other solid fill layers were set to rectilinear.  This nice Moire pattern appears in the bottom of the pad. The black smudge was acquired when I jacked up the car for the video.  Next time I'll take photos before I test a print under load.

Now I'll have to print a jack pad to fit my wife's car...

BMW jack pad dimensions

BMW jack pad printing with 50% infill in fluorescent green TPU.

Done.



The Fusion360 models for Audi and BMW jack pads are here.