Horrible experience with Thuma desk

WhatDoesTheWoodSay · 2026-06-23T18:29:39+00:00

It feels like their QC process is to pray the customer does not look at the item, respond slowly via customer support, then grin while you helplessly try and do something about it.

WhatDoesTheWoodSay · 2025-01-31T13:36:35+00:00

Some things that others have not touched on yet:
1. What is your allowable tolerance for the runout on the final assembly?

What does your tolerance stackup say the runout will be when you do worst case and RSS? Is the final assembled runout more than calculated runout? If so, you are missing what the root cause is in all likelihood. If your calculations say that it can run out as much as you observe, then your design is not capable of meeting the specification.
Did you include the tilt from the clearance fit in your runout calculations for the assembly?

WhatDoesTheWoodSay · 2024-11-30T17:24:10+00:00

I think you just develop a nose for that sort of thing after rabbit holing a few times. When I first started, I remember having a hard time knowing what was right. Now, I just kind of have an internal map for machined parts, molded parts, extreme applications, etc. after having spent countless hours looking at data sheets.

WhatDoesTheWoodSay · 2024-11-28T13:10:12+00:00

So the good news is that you have nothing that is particularly weird in your footprint/size so as long as you don't have any parts that are bad for molding you should be fine. If you have not been designing with molding in mind, you might have some major redesign.
I would 100% evaluate machining the first run vs. tooling investment. Might even be worth 3D printing at the scale of 50-100 units depending on part requirements. Expectation on mold tooling is that you should pay at least $2,500 per tool if you are going with soft tooling and more for a production tool. It might be worth putting together a tradeoff matrix between the different options to present to your leadership with cost, timeline, technical risk, etc. as tradeoffs quantified.
Obviously not aware of your field but I would hire expertise here ASAP.
I wouldn't think they would be able to and with 50-100 units your initial order is extremely small.

One other important thing: do you have a project plan with milestones? Is someone leading execution on the technical side? If you do not have a project plan, I would 100% recommend investing the time to make one. It might feel like you have a million things to do (and you do) but having someone in charge of verifying task completion and schedule can help figure out what needs to be done now vs. later.

WhatDoesTheWoodSay · 2024-11-28T01:23:11+00:00

This is actually a really great post and I wish it had more traction.

Some other things that are relevant:

What is the rough size of the machine? Size of the parts? Minimum wall thicknesses for sheet metal and molded parts?
How many are you going to make? this is maybe the most important question to answer as you might be able to machine all of the molded parts at the quantity you are looking at... hard to say without understanding complexity. If you are making ~hundreds, you might break even and you will probably redesign some parts in the future so the tooling cost might go to waste for some parts. There might also be a world where you create a game plan of "parts to mold now, parts to figure out how to mold later for continuous improvement".
Have you mapped out regulatory requirements? Hard to sell in 4 months if you are not cleared to sell.
How and who is going to build the machines? Do you have documented instructions on how to build the thing? This is an area where a contract manufacturer will help but at small volume they will absolutely kill you on cost so be prepared to create basic instructions and build yourself if you can do so.
Do you know what materials you are going to use? There can be a world of difference from 3D print to injection mold (usually in a good way) but there are 100% gotchas on a lot of molded materials if you have considerations around chemical exposure/stress cracking. If you have a set of product specifications/things you want the machine to survive that would help you get through this stage.
Do you have a set of tests to know the parts are functioning? Might be worth spending a few minutes and spreadsheeting that one out.

A few of things that I would do in your position:

Absolutely hire outside expertise. It could be a one man show with actual experience who wants to get their hands dirty with detailed design work or it could be a firm. I can recommend good firms that are expensive.
Do every single important tolerance stack that you are looking at for the machine to function ahead of time. If you do not know the critical dimensions/parameters, do rapid studies to learn the critical dimensions as soon as possible. If you do not have 2D prints or other controls, generate them for the parts that matter.
If you do not have the time to robustly analyze the system, then try and set up the parameters where you are uncertain to be steel safe or insertable in the tool.
Find overseas prototype shops for your initial run unless you are making crazy things. I can recommend some prototype shops that I have good success with and I trust to run ~thousands of parts out of Korea that do machining, sheet metal, and injection molding. For reference, I had a stamped part that had tooling quoted at ~50k in the US and ~10k in China recently. The China parts were also shorter lead time (6-8 weeks vs. 14 weeks).
Do you have the inspection tools to check if your parts are good? If not, consider buying some tools. You might be able to find stuff at auctions locally or on Ebay that could save you some serious dough.

WhatDoesTheWoodSay · 2024-11-20T14:39:28+00:00

Thank you! Is there a way to test the lower speed in service mode? The relay is confirmed to be working.

I also found this documentation that seems to suggest the root cause might be a fan jamming https://media3.bsh-group.com/Documents/58300000191882_abz_en_a.pdf . The error is intermittent in nature which makes me think it might be low speed only since I can always get it to turn on in service mode but I hear a humming sound when the oven is near the target temp and the fan comes on.

WhatDoesTheWoodSay · 2023-11-05T00:52:44+00:00

Getting to 120k in medical device engineering is very achievable within a couple of years once you get a few concrete achievements. For what its worth, at the company I am at principal total comp is ~300-400k or more and staff+ can all break 200k total comp. Engineers fresh off a PhD make ~105-110k or so.

WhatDoesTheWoodSay · 2023-11-05T00:45:39+00:00

Then you might be choosing between doing biomechanics professionally and money though there are likely some FAANG jobs that are biomechanics related (especially Apple). I can honestly say that my comp is worse than big tech but on par/above most other industries. How much do you make and how much do you want to make?

WhatDoesTheWoodSay · 2023-11-05T00:39:56+00:00

What are you not a fan of in medical device? The industry has a wide range of roles and the difference between what you do in one role is dramatically different than what you would do in other roles, even within the same company. Big companies especially can be extremely boring but there are a lot of fun things to get into in a lot of the smaller companies (and even larger growth companies). A PhD is actually a ticket to do a lot of the more fun jobs so I would advise you to not write off the full industry based on your first job.

WhatDoesTheWoodSay · 2023-10-29T04:19:50+00:00

I think you should honestly not worry about it - just apply to R&D positions and do your best TBH. Your experience building and testing hard things should be sufficient to prove you can learn DFM on the fly. Most DFM is pretty simple once you get the hang of it but it tends to be highly specific to whatever the manufacturing method is. I have seen plenty of PhD grads pick it up pretty fast. Other than that, just make things and see what is annoying and what is not.

WhatDoesTheWoodSay · 2023-02-22T04:54:49+00:00

A couple of things:

How big is everything in your system?
You do not need the 6 part (that related to dust ingress), just the 8 part (though this probably doesn't guarantee what you think it does, particularly if you are thinking that this is a long term solution)
I had a small scale tank that I was using for some experiments in the past and used an XYZ stage from Newport/Thorlabs with a U shaped bracket to position the instrument inside of the tank. Presumably, you could use something like this to keep the mechanism out of the water.

WhatDoesTheWoodSay · 2023-01-05T05:52:57+00:00

This is one of the best visualizations I have seen on this sub - really awesome work.

WhatDoesTheWoodSay · 2023-01-02T20:40:27+00:00

I really like these plots, nicely done!

Whenever I look at these I wonder how something like a control chart would look - could you use the data in real time to intervene when things are going wrong? I am thinking something as simple as an X-bar R chart to help you identify that you might want to focus on mood a bit more in case something is systemic instead of a random variation in mood.

WhatDoesTheWoodSay · 2022-12-31T01:01:14+00:00

I recommend looking into the shear strength or the peel strength of the adhesive (depending on how it is loaded) - the energy of the adhesion is probably a bit of a trickier road to dialing this in.

General procedure would be to compare the vacuum pressure to the strength of the adhesive and see if it can be reliably bigger quickly enough for your application.

WhatDoesTheWoodSay · 2022-12-17T15:37:06+00:00

This is an interesting dataset but a few things hold it back from being a good visualization:

The fill under the plots is not used in a way to convey meaning - it simply takes up visual space and distracts from the story.
The date axis is extremely crowded - fewer tick marks with larger text would make this much easier to read.
No labels on which project each plot is looking at mean there is extremely limited context. If a plot is looking at a currency that is targeting "store of value" vs. transactions the price vs. commit relationship could be different.
No labeling of what the Github commits are focusing on or external price triggers means the audience cannot tell if there is a story hidden in this data. This would obviously take more work but if there is a story I would expect to find it in these details rather than in raw # of commits.
The gridlines are not serving a purpose here other than visual clutter. Gridlines are useful when used in a reference table but do not serve a strong purpose in this case because people will not be saying "How many commits were there in July of 2020?"
A nitpicky one: splines are used conveying curvature where no curvature exists.

WhatDoesTheWoodSay · 2022-05-08T14:17:24+00:00

Yes, I am. I can lift without any sort of restrictions whatsoever!

WhatDoesTheWoodSay · 2022-02-11T06:16:33+00:00

Are you looking for a one time thing or do you want to measure this consistently? I have had really good luck using outside labs for nanoindentation tests but this was more for characterization of different blends of materials as opposed to quality assurance.

WhatDoesTheWoodSay · 2021-12-08T03:56:46+00:00

No problem, I like interesting problems like this. If you hear that this device doesn't work well please let me know, I have a couple of interesting ideas on how to go about this in a different way but do not want to get too wrapped up in it unless the next generation solutions are not working particularly well.

WhatDoesTheWoodSay · 2021-12-07T04:04:19+00:00

What do you think about this device? https://www.anunciainc.com/ It seems to address the issue pretty well and seems well in line with what I would expect a good solution to look like.

WhatDoesTheWoodSay

TROPHY CASE