samleemc
Posts: 3
Joined: Mon Dec 05, 2022 12:16 pm

Invisible "Printer" Coffee Table

Mon Dec 05, 2022 12:52 pm

Hi All,

We have just moved into an apartment and we have a relatively big printer. My wife and I look around the house and the best spot to move the printer is on the coffee table "area" which is between the sofa and the windows.

As a DIYer, of course this spark my another idea to DIY a coffee table to some how "hide" the printer when it is unused.

There are 2 ways of doing so
1. Pull the printer from the front panel with a hidden cart
2. Elevate the printer to the top with LED lightshow and holy music :D

Image

Of course the second one is more challenging and fun!

I have experience developing application on Raspberry pi, so, lightshow and music is not an issue.

However, I am not a trained mechanic, hence, I would like to seek for everyone's wisdom here for my questions below.

The printer I have is HP - m283fdw, the printer itself is roughly 20kg, but with the platform, and the motor itself and anything on top of the coffee table potentially, I figure the load will be MAX 30kg

1. Mechanism
I am planning to put 2 gear rails on the left and right side of the elevating platform, support by 4 steel cylinder rail to guide the lifting moving.
Is there a better way to do it?

2. Motor selection
I am wondering if I should go for Stepper motor or Servo Motor? I can't really figure out what is a better choice even after googling for some time.

3. How to stop?
Once the printer is lifted to the top, it will need to stay in that position for some time while the user is scanning or printing. I know Stepper motor can hold the item with the holding torque naturally, but I am not sure if the holding torque is enough to hold the 30kg load. I think I will need a mechanism to stop and hold its position. Any suggest on how to do this? I have seen post that suggest people can use Solenoid push pull...but even after YouTubing it, I can't really figure out how it can be used.


I know all the above question can be quite basic for experienced DIYer or mechanism, but please share any experience about this and don't hesitate to let me know if I missed any information needed.

User avatar
rpdom
Posts: 21137
Joined: Sun May 06, 2012 5:17 am
Location: Chelmsford, Essex, UK

Re: Invisible "Printer" Coffee Table

Mon Dec 05, 2022 2:12 pm

Threaded rods in each corner passing through a nut fixed in the bottom of each of the steel tubes. Each rod is connected together via sprockets and a chain. Drive the chain one way to raise the printer. Drive it the other to lower it. Have limit switches at top and bottom. No need for a stepper or servo, just an ordinary motor to drive the chain. The platform can't move unless the rods turn.
Unreadable squiggle

samleemc
Posts: 3
Joined: Mon Dec 05, 2022 12:16 pm

Re: Invisible "Printer" Coffee Table

Mon Dec 05, 2022 9:46 pm

rpdom wrote:
Mon Dec 05, 2022 2:12 pm
Threaded rods in each corner passing through a nut fixed in the bottom of each of the steel tubes. Each rod is connected together via sprockets and a chain. Drive the chain one way to raise the printer. Drive it the other to lower it. Have limit switches at top and bottom. No need for a stepper or servo, just an ordinary motor to drive the chain. The platform can't move unless the rods turn.
Thanks! I get the idea, but I have 2 questions regarding the actual implementation.
1. How to "fix" the sprockets to the threaded rod?
2. How to fix the rod so that they don't move? X-Y axis is easy as we can drill a small hole so put the rod in, but how to ensure the rod doesn't move vertically when the chain drive them?
3. Also, if it is a normal motor, as it will not have any force to prevent it from moving after disconnect the power (i.e. when it stop), how to make sure the rod's resistant is enough to stop the printer from falling down?

ame
Posts: 6319
Joined: Sat Aug 18, 2012 1:21 am
Location: New Zealand

Re: Invisible "Printer" Coffee Table

Mon Dec 05, 2022 9:58 pm

Hmm. What can I put here?

samleemc
Posts: 3
Joined: Mon Dec 05, 2022 12:16 pm

Re: Invisible "Printer" Coffee Table

Mon Dec 05, 2022 10:18 pm

samleemc wrote:
Mon Dec 05, 2022 9:46 pm
rpdom wrote:
Mon Dec 05, 2022 2:12 pm
Threaded rods in each corner passing through a nut fixed in the bottom of each of the steel tubes. Each rod is connected together via sprockets and a chain. Drive the chain one way to raise the printer. Drive it the other to lower it. Have limit switches at top and bottom. No need for a stepper or servo, just an ordinary motor to drive the chain. The platform can't move unless the rods turn.
Thanks! I get the idea, but I have 2 questions regarding the actual implementation.
1. How to "fix" the sprockets to the threaded rod?
2. How to fix the rod so that they don't move? X-Y axis is easy as we can drill a small hole so put the rod in, but how to ensure the rod doesn't move vertically when the chain drive them?
3. Also, if it is a normal motor, as it will not have any force to prevent it from moving after disconnecting the power (i.e. when it stop), how to make sure the rod's resistant is enough to stop the printer from falling down?
For 2, will soldering be strong enough for long term use?

ghp
Posts: 3019
Joined: Wed Jun 12, 2013 12:41 pm
Location: Stuttgart Germany

Re: Invisible "Printer" Coffee Table

Mon Dec 05, 2022 11:29 pm

Consider not moving the printer, but lowering the cover. Less mass to move.

ame
Posts: 6319
Joined: Sat Aug 18, 2012 1:21 am
Location: New Zealand

Re: Invisible "Printer" Coffee Table

Mon Dec 05, 2022 11:30 pm

samleemc wrote:
Mon Dec 05, 2022 10:18 pm
samleemc wrote:
Mon Dec 05, 2022 9:46 pm
rpdom wrote:
Mon Dec 05, 2022 2:12 pm
Threaded rods in each corner passing through a nut fixed in the bottom of each of the steel tubes. Each rod is connected together via sprockets and a chain. Drive the chain one way to raise the printer. Drive it the other to lower it. Have limit switches at top and bottom. No need for a stepper or servo, just an ordinary motor to drive the chain. The platform can't move unless the rods turn.
Thanks! I get the idea, but I have 2 questions regarding the actual implementation.
1. How to "fix" the sprockets to the threaded rod?
2. How to fix the rod so that they don't move? X-Y axis is easy as we can drill a small hole so put the rod in, but how to ensure the rod doesn't move vertically when the chain drive them?
3. Also, if it is a normal motor, as it will not have any force to prevent it from moving after disconnecting the power (i.e. when it stop), how to make sure the rod's resistant is enough to stop the printer from falling down?
For 2, will soldering be strong enough for long term use?
Err, that's three questions.

1 Get a sprocket with a centre boss and grub screw. The grub screw grips the threaded rod.

2 Assuming the rods support the weight of the top part there will be a constant downwards force on them. This will stop them floating away.

3 (shall be the number thou shalt count) A threaded rod basically directs force from the thread to the nut. Force on the nut does not cause the threaded rod to rotate (unless you have chosen a thread which does allow that to happen).
Hmm. What can I put here?

ghp
Posts: 3019
Joined: Wed Jun 12, 2013 12:41 pm
Location: Stuttgart Germany

Re: Invisible "Printer" Coffee Table

Tue Dec 06, 2022 7:37 am

You could build a "scissor lifting table", but needs some mechanical skills.

See https://en.wikipedia.org/wiki/Lift_table for some images of heavyweight implementations.

pidd
Posts: 4388
Joined: Fri May 29, 2020 8:29 pm
Location: Wirral, UK

Re: Invisible "Printer" Coffee Table

Tue Dec 06, 2022 8:17 am

I'd use 4 steppers and 4 guides, basically the vertical components off a Prusa i3 3D printer doubled up.

Traditionally lifts like this were done with one loop of string and and a lot of pulleys, lifting all four corners from one motor which is an interesting exercise in design.

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