topic Re: For a model of frozen chips, how do I add liquids at certian stages? in FlexSim Forum

For a model of frozen chips, how do I add liquids at certian stages?

laura_harris — Thu, 08 Dec 2016 12:20:38 GMT

Re: For a model of frozen chips, how do I add liquids at certian stages?

andrew_rooney — Thu, 08 Dec 2016 12:34:36 GMT

Hi Laura,

I'm assuming that you are modelling the process of freezing chips/fries and you want to add a standard volume of oil or water. If this is true then you can treat the volume of fluid as a discrete element.

To model this I'd simply use a Combiner, with the Combine Mode set to Join. The "fluid" will be pulled through input port 2 so that it doesn't alter the flow item image.

I hope this helps.

Re: For a model of frozen chips, how do I add liquids at certian stages?

andrew_rooney — Thu, 08 Dec 2016 14:41:18 GMT

Hi Laura,

Ok, I get the idea. I think it depends on how much detail you need.

Firstly, if there is no effect on throughput then you may not need to model the fluids.

If you only need to model the effect of the removal and then resupply of the fluids as a time delay then you could use a change over time in the processor, so every 300 items there is a delay - use the Processor, set up time, and use "different time for nth item". Set the time for other items to 0 and for the 300th item to the change over time.

If you want to actually model the resupply then you will need to count the potatoes processed. There are many ways to do this but I guess from your question that you are just starting with Flexsim so the simplest way I can think of is to use a Combiner. The logic is that the Combiner will consume 1 unit of oil/water for each potato, and every 300 potatoes the stock of oil/water needs to be resupplied. Set the Combiner to pull 1 potato and 1 unit of fluid from a queue (no need for tanks / pipes or fluids). Fill the queue from a Source set to a 0 inter-arrival rate and in the queue tick "Perform Batching", batch size of 300 and Flush Contents between batches. This contents of the "fluid" queue will fill up to 300 and be consumed over time.

Re: For a model of frozen chips, how do I add liquids at certian stages?

arunTTT2P — Thu, 08 Dec 2016 15:16:46 GMT

Hi Andrew Rooney,

I think this idea may affect the performance of the model, particularly considering the potato as a single flow item the number of flow items in the model will be very high. Correct me, if I have understood it wrongly.

Regards,

Arun KR

Re: For a model of frozen chips, how do I add liquids at certian stages?

andrew_rooney — Thu, 08 Dec 2016 15:30:00 GMT

Hi,

Completely agree. If performance is an issue then you can use 1 flow item to represent, say, 20 potatoes. You will need to multiply up any processing times and any results.

Re: For a model of frozen chips, how do I add liquids at certian stages?

andrew_rooney — Tue, 03 Jan 2017 16:34:06 GMT

Hi Laura,

The Combiner pulls an item through Port 1 before pulling any other item, and, if you are using the Join setting then the item that leaves the Combiner will have image of the item that entered through Port 1. You can swap the port order around in the Combiner's General Tab, select the Input Ports item at the bottom of the list and swap the order of the ports around. This should fix the image.

I would probably not model the actual water, but would think of it in a more abstract way. I would think of the water as a counter that will cause the next batch of water to be delivered when the counter reaches 300 (or whatever number you have decided upon).

I have attached a really simple model that shows this. The Potato source feeds into a queue that feeds into Port 1 of a Combiner, set to Join.

Water Source has a 0 inter-arrival rate and feeds into a queue that has Perform Batching checked, and batch size of 300 - so it will build up a quantity in the queue of 300 parts. Flush Contents between batches is also checked and this causes the input to the queue to be closed while the queue is emptied, and all the water is used up. When the queue is empty then the input opens again and the next batch is delivered.

I hope this helps.

Re: For a model of frozen chips, how do I add liquids at certian stages?

laura_harris — Sun, 08 Jan 2017 11:20:20 GMT

robotics-2-v6.fsm

This is my model so far. With the last part of the simulation, I want the chips to either go into a large packet size or a standard packet size by percentage split.

Once the packets leave the combiner I want the standard pack to be one colour and the large to be another colour. I've got it so one pack leaves a different colour once combined but I'm unsure how to get all the flow items to change colour once in packets.

Looking at it, I think I will have to add another combiner to pack into boxes.

Also on your initial post, can I get it so when every 200 flow items pass through the combiner (ie washer) a water flowitem goes onto the combiner and this continues?

Thanks

Re: For a model of frozen chips, how do I add liquids at certian stages?

andrew_rooney — Mon, 09 Jan 2017 10:08:41 GMT

Hi Laura,

From what I can see in your model I'd probably use the Join option in the Combiners. That should stop the mix of colours and the incorrect positioning of the flow items that you are seeing.

Before you proceed much further I would check all of the process times - I think you still have the defaults - and I would turn the conveyors and processors round the correct way.

I don't think that you need the Separator2 object - you could use the Conveyor's Flow Tab and change the Send To Port rule to By Percentage. I also don't think that Separator1 is needed - you have used the Join option in the Washer so the settings you have used in Separator1 just remove 5% of the flow items to Sink1. If this is for wastage the you can use the Flow Tab in Conveyor 2 to get the same effect. If you are using this to separate out the water then I would do this in a different way.

To top the water store up to 200 set the Source Inter Arrival time to 0 - so it instantly tops up the store - and the Target Batch Size in the store to 200. At this level and given the size of the model, I wouldn't worry about run speed.

If you want to collect 200 potatoes and 1 unit of water then just collect 1 unit of water through Port 1 and then 200 Potatoes through Port 2 of the Combiner, use the Pack option in the Combiner. This will let you wash all 200 potatoes at the same time, if that is what you want? Once the Wash cycle is complete then you would use a Separator, with the Unpack option set, to send the Water to Part 1 and the 200 potatoes to Port 2.

I hope this helps.

Re: For a model of frozen chips, how do I add liquids at certian stages?

laura_harris — Tue, 10 Jan 2017 14:17:36 GMT

Thanks so much for your explanations, this simulation is due in on Sunday so I really appreciate your help.

I've changed the conveyor to the percentage function.

For separator 1, it's a length and size grader so I feel there does need to be some kind of a processor, the potatoes that don't meet the requirement go into the sink, this will be 5% of flow items.

For the washer, yes I want it to pull one 'water' and 7 potato flow items (each flow item represents a high volume of potatoes), then theses items to stay within the combiner for an amount of time, then the used water flow item to exit the simulation, and the 'washed' flow items to carry on through the simulation. I've added a separator like you suggested, how do you mean sending the water to port 1? Is it best to use a join or pack or batch function here?

Would I need to add a separator every time I used a combiner to add liquid such as for the blancher?

With the packaging, I want it to pull say 5 packages for every flowitem, however when I click on the combiner and go onto the 'combiner tab' it only lets me change the quantity from port 2? When the packages leave the combiner, is it possible for them to change colour, depending on if they have been packed in a standard or large size from the relevant combiner?

Thanks again

Re: For a model of frozen chips, how do I add liquids at certian stages?

laura_harris — Tue, 10 Jan 2017 14:22:47 GMT

robotics-2-v6-after-edit.fsm

Re: For a model of frozen chips, how do I add liquids at certian stages?

andrew_rooney — Tue, 10 Jan 2017 15:02:09 GMT

Hi Laura,

Ok, I understand what you are doing with the grader and it makes sense.

For the washer, from your description, I would use the Combiner, set to Pack, to collect 1 Water through port 1 and 7 Potatoes through Port 2. You will then need to connect a Separator, set to Unpack, to the output port of the Combiner. Connect Port 1 to a Sink and Port 2 to to the next conveyor.

The Combiner will pack the 7 potatoes into the water, and the Separator will unpack the 7 individual potatoes from the water. Normally you would pull a container, like a palette or a box, through Port 1 of the Combiner but in this case the Water is the container.

You will use this general structure over and over again, for the blancher etc. The default rule in Flexsim is that the Container (palette, box, water etc) is pulled into a Combiner through Port 1, and is sent from a Separator through Port 1. The parts being packed are pulled into the Combiner through Port 2 and pushed from the Separator through Port 2. Just remember to always check the order of the ports - it saves a lot of head scratching later on.

In the Packaging Combiner I think you will need to swap the ports around - look at the Combiner, General tab and in the Inputs section at the bottom of the properties box and order the ports correctly. I would change the colour of the packaging when it is created at the Soures - then when you pull the packaging through Port 1 of the Combiner it will already be the right colour. You will then place the 5 packages into the coloured flow item (big bag or box) and I would probably use the Combiner Join option at this point.

I hope this helps..

Re: For a model of frozen chips, how do I add liquids at certian stages?

laura_harris — Wed, 11 Jan 2017 14:42:04 GMT

When packaging, with the combiner used to put the completed packages in boxes, the simulation the boxes are produced but stay separate, is there a way of packaging 5 flowitems together in a box and staying the same colour? I'd like 5 packets to be put into a box then 4 boxes onto a palette to then be transported to the racks via a robot and a transporter. Or should I just delete this part and simply package the bags onto palettes?

Also, for optical sorter 1, after the steam peeler 5% of items go to the queue, as they need peeling again. Can I get an operator to move the flow items back to the queue near the steam peeler when there is 5 flow items on the rejects queue, and then for the steam peeler to process the rejected items first as they have been in the simulation longer.

Can another operator then go to the fryer processor, and simulate a 'breakdown' every 3 hours say. The operator has to clean the fryer and therefore stop production for an amount of time. I will add another fryer so while either is on down time, 100% of the flow items go through one, and when they are both working the split is 50/50. I know I need to use the S key for operators.

Also once the pallets are on the rack, do I need to simulate them leaving?

Thanks

robotics-2-v8.fsm

Re: For a model of frozen chips, how do I add liquids at certian stages?

andrew_rooney — Wed, 11 Jan 2017 15:47:42 GMT

Hi Laura,

The Pack option in the Combiner and Unpack option in the Separators work together to let you put things into and take things out of a container. The Combiner Join option actually deletes the parts and only leaves the Container, usually a palette or a box in the model. You would use join when there is no need to unpack the container and don't need the visual representation of the contents

I think you need to use the Join option in the Combiner to put the 5 bags into the box: collect the box through Port 1 and the 5 bags through Port 2.

Next use the Pack option to put 4 boxes onto a palette. If you miss the step to put the bags into boxes then I think the model will look wrong.

If you want to use an Operator to move items then connect the operator and in the Flow tab tick Use Transport. Use the Batching, Perform batching setting, set to 5, in the rejects queue and don't forget to set the Capacity of the Operator to 5.

If you want failures then use the Breakdowns function in the Fryer processor (as you have done) and set the Down Function to Stop Object and Call Operators. It will pull the operator connected to the Centre Port 1 (connected with the S key). The object that feeds the two Fryers should have its Send to Port rule in the Flow tab set to Round Robin if Available.

Hope this helps

Re: For a model of frozen chips, how do I add liquids at certian stages?

laura_harris — Thu, 12 Jan 2017 08:59:37 GMT

I'm having a few problems when I add the queue for the flowitems waiting to go back into the peeler. When I connect this queue and the peeler, then run the simulation the flow items stop at the peeler. When I disconnect these objects and run it works fine.

Also for the fryers, can they be scheduled breakdowns, I've selected this option but how do I set the times as to when they will break? Also how do I call the operators when they have scheduled down time to clean out the oil? Do I connect the fryer to the operator, I connected the dispatcher to the fryers but it doesn't seem to work. On break down I'd like them to be red but then change back to yellow.

Can you just clarify how to change the colour of an object produced by the source also, for the packaging I have done the flow item to change colour on exit, but I'd rather the actual source produce either blue or red items for the different packaging.

For the transport onto the racks including the robot do I use the S key?

Thanks

robotics-2-v8.fsm

Re: For a model of frozen chips, how do I add liquids at certian stages?

laura_harris — Thu, 12 Jan 2017 08:59:37 GMT

For the transport onto the racks including the robot do I use the S key?

Thanks

robotics-2-v8.fsm

Re: For a model of frozen chips, how do I add liquids at certian stages?

andrew_rooney — Thu, 12 Jan 2017 11:49:51 GMT

Laura,

It looks like the Reject loop is working correctly. Remember that when queues get filled to capacity then they will cause a back-up and choke the system.

You can't connect your "Optical sorter 1 rejects queue" directly onto the Steam Peeler combiner. Either feed onto the conveyor that feeds the Combiner or create a dummy queue with a capacity of 1.

Fryers MTBF: You have used the default times so you need to change these. Planned/scheduled maintenance is generally entered as a fixed value to the First Failure and Up Time fields. As I said previously, use the Down Function, Stop Object and Call Operator option to call the Operator.

Why not have 2 Box Sources? Set the Interarrival time to 0 so that there is always a box available. Change the box colour by using the OnCreate trigger and set the Object colour to whatever makes sense.

Yes, use the S key. You haven't connected the Packaging Combiners to their Output queues, so they won't operate. Same comment for the feed to the racks.

You still have default times used for most of the processors and combiners.

Re: For a model of frozen chips, how do I add liquids at certian stages?

laura_harris — Fri, 13 Jan 2017 10:00:27 GMT

The reject queue is working fine now.

For the fryers, there seems to be some kind of an error message that comes up, I've tried deleting the objects and putting them in again. It says something about previous errors. The colour change and calling operators is fine, but I don't want them to break down at the same time as they are scheduled down time, do I define this in 'first failure time' or 'up time' and 'down time'? I'd like them to have scheduled down time 2 times a day but not at the same time, then be working at every other time.

Also can you just clarify what you mean by connecting the packaging combiners to their out put queues, also regarding the racks please?

Thanks

robotics-2-v9.fsm

Re: For a model of frozen chips, how do I add liquids at certian stages?

andrew_rooney — Fri, 13 Jan 2017 10:33:50 GMT

Laura,

The error message is caused by the blank you have left in the First Failure Time. Just enter when you want the first maintenance to take place. If you don't want them to stop at the same times then offset the first failure times, so enter (for example) 100 into OilCleaning1 and 200 into OilCleaning2 or whatever values make sense, or using the By Time of Day function if that works better for you

Up Time is the time until the next failure. Again, you can use the By Time of Day function to set when the Maintenance should occur.

Delete the error messages from the Console window so that you can confirm they are fixed.

You will need to connect, using the A key, the two final combiners to the Queues 3 and 69, and then those queues to the racks. At the moment there are no Output ports from these objects so the parts can't leave them. I would also disconnect the Robots from Queues 3 and 69 - I guess you want the transporter to perform the movement into the racks.

Andrew

Re: For a model of frozen chips, how do I add liquids at certian stages?

laura_harris — Fri, 13 Jan 2017 11:53:52 GMT

Okay thanks the error has gone. I don't understand how I specify when the machines will break down. On the break down tab the functions, it has 3 fields, 'first by failure', 'up time' and 'down time', all these I can add 'By time of day', but I can insert any number on the time table it produces if you understand. So for example of first time faliures on fryer 1, I have put a number 1 next to 2am and 11pm, does this mean they will break down at 2am and 11pm.

Where do I put the numbers 100 and 200 as you said above? is this on the timetable or which field? As they are still going down at the same time.

Thanks

Re: For a model of frozen chips, how do I add liquids at certian stages?

andrew_rooney — Fri, 13 Jan 2017 12:32:00 GMT

Laura,

I think the easiest thing for you to do is to enter time units and not to use the tables. Your model is running in seconds, so if you have a 24 hour day then 3600 seconds per hour, and 86400 seconds per day.

If you want to fail firstly at 6 am then enter the number 21600, which is 3600 * 6. If you want it to fail every 12 hours after that then enter 43200 (3600 * 12) in the Up Time field. Just delete the text that is already there - you don't need to use the picklists.

Once a repair is complete then the next failure is scheduled, so you may need to subtract the repair times from the MTBF.

A Time Table would be a more accurate option for Planned Maintenance, but you probably don't want to start learning a new thing just now.