Small 3D Metal Printed Part

[Julie AnnParticipant @julieann]

The tension spring on the reversing levers on my traction engines goes from an eyelet on the tongue to the reversing lever, rather than the more common extended pin on the operating lever to the reversing lever.

The use of an eyelet is prototypical Burrell according to Gilbert, so I wanted to replicate same. Designing an eyelet in 3D CAD was simple. But I could see making them being rather fiddly. So I decided to get them 3D printed in stainless steel. If nothing else this would be in the nature of an experiment to see how a fairly small part would turn out. The answer was surprisingly well:

I went with PCBWay as craftcloud3d use external printing companies and the prices are now astronomic. I only needed two eyelets but bought ten. Total cost was $60 of which half was shipping. I was charged £45 on my credit card which is not far off the normal exchange rate. Delivery was eight days.

The shank is a few thou undersize which means I will have to rethink my means of attaching the eyelets to the tongue. I was going to use a 10BA thread, but don’t really want to buy 11BA taps and dies as I can’t see myself ever using them again. Since I have spare eyelets I can afford to experiment with a few ideas.

Julie

[Alan Wood 4Participant @alanwood4]

JLCPCB are an alternative offshore source.  They seem more interested in small hobbyist quantities and their overall cost is significantly lower.   They offer both PCB and 3D printing but their material selection is reduced on that offered by PCBWay.

[Frank GorseParticipant @frankgorse]

Julie Ann, I have 11BA taps&die which I’ve never used and probably never will. You’re more than welcome to them if that helps. Frank

[JasonBModerator @jasonb]

Nice little eyelets, would M1.6 do the job?

I’m happy with what I have received from Craftcloud and their external printers. Just out of interest, I uploaded a part I was working on at the weekend to PCBWay and in Stainless it was £270 + Shipping compared to £150 all in. Or in aluminium £152 + Shipping compared to Craftclouds £107, again all in cost with VAT and Shipping.

JLC between the two for stainless and I can’t see them listing aluminium.

 

[BazyleParticipant @bazyle]

Potential for things like coupling hooks and buffers. The trick with small parts is to put a bunch of them on a sprue disguised to look like a complex item so they are less likely to spot you are avoiding their piece-part markup.. They don’t like small parts that can get lost and are fiddly to clean the supports off, depending on their process. The gaugeone3Dcircle often discuss these issues.

[JasonBModerator @jasonb]

Craftclud have no problems with you joining parts with a sprue. Infact if you tell them what is sprue and what is the part they will not bother about fettling the sprue so you will probably get charged less. Infact he even contacted them and they advised him to join the parts and also told him the minimum sprues sizes to use. He was not able to do the 3D CAD to get the part smade.

I drew these valve spring retainers for someone a few weeks ago, They are making two twin cam V8 engines so needed 64 identical parts. we went with 4 sprues to keep the O/A size down with a couple of spares on each. Priced for printing 64 individual items was going to be a several hundread. Price for the 72 on sprues was £64.

Read it here, you wil nee dto be a registered member to see some of the images which are posted asattachments.

https://www.modelenginemaker.com/index.php?topic=5142.msg307822#msg307822

[Julie AnnParticipant @julieann]

Plenty of ideas to mull over, thank you.

I did a sanity check by downloading the STEP file to CraftCloud again; result was £55 for one off plus shipping.

Frank: Thank you for the generous offer, PM sent.

The shank as printed is a shade under 1.5mm, which is not a standard metric size although taps and dies are available at a price.

The force from the tension spring is at right angles to the shank so, in theory, a thread is not needed. I am going to experiment with Loctiting the shank in place, or just hammering over the end of the shank into a small chamfer. As designed the shank is a little longer than needed specifically so that was available as an option.

Julie

[mike TParticipant @miket56243]

Actually, the 72 valve spring retainers on a sprue, referred to by Jason, used so little stainless steel powder and came in at £4 under the metal printer’s minimum order cost. I could have had another 8 spring retainers printed for the same price, but just how many spares do you need?

When you consider the manufacture’s minimum order value and the small package postage, All metal print jobs are therefore going to be around £60 ( does not seem to matter who you go to). So you may as well order as many parts (joined by a sprue) as the minimum order cost allows. A dozen single items will always be more expensive to make than a sprue of 12, as that will count as a single item.

[JasonBModerator @jasonb]

You don’t even need to sprue parts to get them all into the “job cost”, very small items it can help. I got these six done for as much as a single would have cost and no sprue. It is so easy to play with the quantities or add a sprue or other joining method to small parts that it would be silly not to try a few different price options to get the best for your money.

Out of interest Julie, did you get those printed loose or on a sprue?

This is likely to be the next one I get printed, 120mm high. I will also need a cylinder head which I will get prices for as a separate item and also attached at the top on a couple of posts. Originally I drew it with the intension to do it on the CNC with the base flange separate and not much in the way of internal cavities. Now with 3D printing I can get it all as one, complex cavities and every cavity added reduces the cost as it needs less powder.

I had intended to do the flat fin cylinder that can be seen in the background of the photo above. But maybe I should also go with this version as it would be easy with a 3D print?

 

 

[JasonB]

On JasonB Said:

Out of interest Julie, did you get those printed loose or on a sprue?

As far as I am aware they were printed loose. I didn’t specify a sprue and there is no evidence the parts have been cut from a sprue.

I don’t know if the parts were printed horizontal or vertical, although horizontal would involve far fewer layers. I am not sure a sprue would have helped with these parts. Presumably PCBWay mix ‘n’ match parts from different clients in the same print cycle to maximise use of the machine.

Julie

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